Interesting question, and I find my reaction to it interesting, too. My first thought was of a knife or multi-tool, but honestly, is having that the top priority? I also realized that my approach to survival is influenced heavily by what I am honestly likely to run into in my region. If you told me I was headed out into the high desert or the Costa Rican jungle, I might tweak it just a bit.

Anyway, in no particular order:
1. folding knife or multi-tool (take your pick, opinions vary)
2. military-style poncho (for shelter, catching rain water, etc)
3. water bottle (filled, preferably)
4. bic-type lighter (or firesteel, again, opinions vary)
5. 40' of 1/2" nylon rope

Why the rope? In many emergency and near-emergency situations there is a need for a length for rope to climb, lower, secure, rescue, restrain, protect, anchor, etc., someone or something. I chose the 1/2" nylon because it's strong enough for a lot of applications, but 40' is not too heavy to carry, and it's easy to splice. You can also unlay the strands and end up with 120' of cord, should you need to.

I thought long and hard about cup vs. water bottle, but opted for the ability to carry some water with me. I'll have to work out how to boil it along the way, I guess.

Since I opted for no compass or map, finding that way will require some careful thought. In my region I know the night sky well enough to hold a rough course for most of the night, if it's clear enough. I also know the prevailing wind patterns, so a steady breeze is likely to give me a rough bearing.

No signalling equipment - I am assuming I am mobile and uninjured, or else I would trade a cell phone or at least a whistle for the rope.