My choices (closely related to what I carry)

If you can, put it all inside an aluminum cup or teeny tiny mini-loaf pan. something you can
boil water/melt snow in. dunno if that'll fit
in your pocket. I have this in a nut can that has a plastic lid.

- A small leatherman micra or swiss army knife
- A mini-bic lighter.
- A small firesteel (light my fire scout)
- couple of cotton balls soaked in vaseline
- a small candle or two (ikea tealights)
- duct tape
- 4 safety pins
- 150lb test dacron fishline (for guylines/tieing things, not for fishing)
- a space blanket or space blanket bivy bag
- a small hunk of light plastic painter's tarp (about 9x7 or bigger if it'll fit)
- a small button cell powered LED light.
- a small compass
- some light nylon rope or paracord (I have mine wrapped around the outside of the can)

work up from there.

I don't bother with any first aid sillyness (you're in a rescue copter) beyond duct tape,
and I don't bother with fishing or hunting sillyness, you're not going to be trying to live off the land. you're going to be trying not to die of exposure or thirst while you wait to be rescued. I don't bother with water purification either, if I have a fire going I can boil, but more than likely just drink it untreated - nothing in the water will do me any near-term harm.

If you could fit something like an Integral Designs silponcho, even better, but that's a bit bigger. - The above in a nut can, with the silponcho always goes into to my daybag if I'm dayhiking - in addition to anything else I take.