You should be wearing most of what you need for a night of survival. Don't skimp on clothing.
If you really worry about what might happen to you, then a copy of your last will and testament, signed by at least two witnesses, properly notarized, and double sealed in plastic bags, taped to your body with waterproof tape. If you decide at the last minute you made a mistake, it can still be used as tender to start a fire.
I would take a bottle of Laphroaig scotch whisky, or at least a pint flask, but that's just me.
It's interesting to note that during the battle of Stalingrad, a Russian general always under reported his losses. It wasn't to make his battle performance look better than it was. The main reason being, was that his vodka ration was based on the number of surviving soldiers he had left. The more vodka his soldiers had, the better they survived the harsh conditions, and the harder they fought. Survival is 90% attitude, and it's the first thing you will read about in military survival training manuals. Anything that prevents you from having a defeatist attitude is worth having, doesn't matter what it is, even if it's considered worthless by most other people.