A ski mask and a baseball bat...
hard boiled eggs (I just saw a grocery store carrying precooked boiled eggs in their deli section. They were whole)
shaker bottle + good protein powder for simple shakes
any kind of nut/seed
GOOD protein bars - hint there are very few good ones on the market and Biotest is the best of those few
all manner of other canned fish (I especially like kippered fish, the one in the plaid coloured can)
liquid egg whites (yes I have drank these by themselves and mixed in shakes)
extremely dark chocolate bars (I am talking 85% neighborhood)
any kind of dairy you like and can digest, especially yogurts
Some of that presumes you have a fridge. If not, just forget I mentioned those items.