I found the bolts at work and did a quick layout of all the stuff that I have that's Stalkery. Unfortunately my gas mask is kept in base storage and I was out of vodka.
The silver package next to the smokes are Russian lifeboat rations:
I haven't.
I just did a quick google search and it turns out you can get 72hr ration packs as well!
It has 2400Kcal of consumables inside.
https://www.amazon.com/ORIGINAL-EMERGENCY-SURVIVAL-MILITARY-2400Kcal/dp/B01FPLP1QQ