+1.

And while remaining assertive and calm in that position, you might as well enjoy that hearty lunch of yours....

You can't react to every foreign noise to your surroundings. Without any environmental indicators like sirens, smoke, screaming, car screeching, or follow up noises that last for several seconds like the roar of a building collapsing, or gun play all you can do is get PREPARED to move.

You don't know where to move, or how to move but you get ready to move by making sure you can do so quickly. Reason #1 for having a EDC within arms reach if not on you.

The preferred response is to immediately scream "incoming" at the top of your lungs, quickly dip you fingers into your water glass and then into the ashtray, shoulder roll behind the potted plants, smear your face with the ashes, pull your weapon, and while maintaining your very best bug-eyed and throbbing-vein expression shout that "Charlie is in the wire" and scan the room with your sidearm. Lacking a firearm hold a butter knife in an aggressive stance. A large soup spoon is a good option and adds a bit of comedy relief.

I'm always leery about the whole survival mindset riff. Those who have it don't focus on it. Those who worry about it don't have it. Most people who worry about it avoid the clear. calm awareness needed and instead adopt some macho BS like: 'have a plan to kill everyone you meet'. Or some form of generalized hyper-alertness and nervousness that usually guarantees they are half exhausted before any emergency rolls around. Those are not a survival mindsets. They are paranoia and psychopathology disguised as preparedness. It is also a very fine way of wearing yourself down, alienating people who might help you, and a long-term strategy for dying alone.

I think you did well enough but quite frankly I would sit back and enjoy my meal. If you were part of a planned emergency response and had reason to think something might be going on you might phone the dispatcher and make sure they have your cellphone number in case they need people.

A single explosion is not much to go on. A truck driving over a sealed two-liter plastic bottle makes a noise like a shotgun going off. A transformer going bad typically has a 60 cycle growl often followed shortly by a rather impressive explosion. Living in Florida we got sonic booms every time the shuttle landed. Typically a double boom like two deep thunderclaps. The military also provides the occasional sonic boom.

Seattle is below a mountain that will some day make a very large boom. But jumping up based on a single distant explosion and clearly inadequate information is a waste of effort. I suspect the urge to jump up and 'do something' indicates you are too nervous and need to unwind a bit. Big emergencies develop over time, those that don't have no effective response, and the world will let you know when you need to act.

There is no need to 'strain at gnats' or jump at every loud noise. Save your energy for things that matter.

LOL! Thanks, Art, I needed that.

In my part of the world, with active oilfields all around, a boom doesn't make me think of hostile activity. It makes me wonder if a pressure vessel or train car has popped. So my first reaction, sans smoke or sirens, is to note the wind direction. Just in case my lunch is about to be spiced with a cloud of H2S or ammonia.

Thanks everyone for your replies to my "unknown BOOM" situation. I am glad to know that fewer Rambo's exist (or at least post) then I sometimes imagine. A summary of what I got out of the responses was:

No need to take any large action until you have enough information to know what action is appropriate. However being more alert and actively seeking more information would help you determine the correct action.

Most people were in agreement that of the reaction options I provided, the following was the best, given the limited information available.

11. alertly evaluate the situation with all your senses and with no more information, immediately pay your bill and leave

However there was some discussion on leaving immediately or staying until time or more information determined it was safe to leave.

Other information I thought was useful:

Additional indicators of problems -
Does the building you are in still have power?
Does your cell phone still have signal?
Are people outside your immediate surroundings acting strangely?

Additional sources of information -
TV's that exist in many businesses.
Radio's that play background music in many businesses.
Cell phone (tweets, web, text messages, etc.).
Someone who just came INTO the building.

Things to do -
Go into a heightened (but not necessarily hyper) state of alertness.
Watch the actions of people inside AND outside the building.
Re-check where all visible exits are. Not just the closest.
Put cash on the table to cover your meal. You can then leave quickly if necessary. You can always pick it back up and pay via a different method if nothing further develops.

Miscellaneous -
Note the time. You will then KNOW, instead of GUESSING, how long it has been since whatever caught your attention occurred.
Drawing a weapon will likely make YOU the bad guy in a situation where nobody is sure what is going on.
Don't rush to leave. If the building you are in is unaffected, then you may be safer inside the building than outside.

Finally -
If you take precipitate action (throwing yourself on the floor, fleeing the building, drawing a weapon), this will likely cause reactions in those around you as well. You may be thinking clearly, but if your actions cause others to panic, you may be responsible for changing a minor incident into a situation that gets you or others severely injured or even killed.

Thanks again everyone, I am working on becoming a better survivor and situational awareness is one of my weaknesses. This kind of discussion helps me determine boundaries on what is too little and what might be too much.

The absurdity of the whole situation fairly negates any rational act. Restricting airspace because the POTUS is in the area? Really??? Gimme a break!

Used to be a full wing of f-15s at McChord. Nice to know that the only response to an airborn threat in the greater Seattle Tacoma area has to count on Fighters from Portland scrambling and doing a full burn. I bet by the time the fighters got into the threat zone, the errant civilian plane was already past the point where a strike would've occurred.

Stupid. My response at hearing the sonic boom and the subsequent report, laugh my A$$ off!

I heard both booms - they sounded just like sonic booms alright. I was sitting on the outside deck at Ray's Boathouse on Shilshole Bay with my wife. We enjoyed the rest of our meal, paid and went across the street to go over our wills with our estate planner. If the booms had been something more dire, I can't think of a better place to be than on the sun deck at Ray's. Or planning your will.

Great topic, Wolfepack. It reconfirms that I really should carry a small radio with me when out and about. I got an iPod Nano with built-in FM radio fro Christmas but it usually just sits on my desk.

I'm not sure how I would have responded. I would like to think my response would be somewhat based on what I knew of my surroundings. If I were downtown away from any chemical plants or refineries I would have probably headed indoors into a store or something for a bit. If I didn't see anyone running in terror I would assume it was safe to go back to whatever I was doing.

-Blast

The fact that a couple of sonic booms caused the 911 system to be overwhelmed with calls surprises me.

I wonder how many of the people that called or attempted to call 911 had enough (or thought they had enough) detail to even allow the police/fire to investigate. Calling 911 to say that you (and half of town) heard a loud noise but you have no idea where it came from or what caused it probably is not very helpful. I wonder if any campaigns are being discussed to educate the public on when they should apply some sort of filter to their thought process before calling 911.

In a perfect world, option 1 with a variation. Delay for a second as I reach for my EDC bag, then hit the floor and make sure my people were with me down there if there is anything that in the first second or so doesn't look that 100% normal. Then begin sizing up information.

However, I've spent most of my life under or near military flight lines- sonic booms are sonic booms. I have hit the deck for other explosiony-noises, but there were two recently returned Gaurdsmen in the room the last time. We all got silly looks, and they looked at me like "who are you, you don't look like one of us". (Big belly, long hair, working on a ZZ Top beard. I don't look deployable as anything other than a paperweight. Or a really, really cranky budda.)

EDIT: LOL @ Susan.