Always an interesting problem - stay or go? Realistically, one of the best resources is a good store of financial resources, both cash and credit (I am assuming realistic disasters, like a nuke meltdown, not the end of the world stuff). in any event, actual events are likely to disrupt carefully laid plans. Here's a real world example.

Some years ago we were disembarking people and cargo at Anacapa Island (SoCal). All of a sudden, the boat gave five toots on the horn (distress signal). He had just been told that a rocket had exploded on the launch pad at Vandenberg AFB (65 miles west), spewing large quantities of bad stuff into the air, and instructions were to evacuate everyone from the island immediately. We did so, and then our captain asked HQ in all seriousness, "Should we go out to sea or return to the mainland (presumably to die with everyone else). We returned to a relatively unpolluted mainland and lived.

On San Miguel Island, much closer to Vandenburg (30 miles) we had about four people on duty. They were instructed to retreat to the ranger station, seal up all openings with duct tape and plastic, and wait for evacuation. A plane was sent and they were evacuated. I don't know if SCBA was involved - it was about one-half mile walk from cabin to airstrip, but they were examined periodically for the next several months.

So there you have bug in and bug out in the same event. Just be sure you have duct tape and your Swiss Army knife handy at all times......