Plastic...
I'm going to assume this means you have no access to tools or cooking methods.
I'd be looking at nuts, beef jerky, chips and salsa, granola bars, craisins, sunflower seeds, etc. I'd do recon on what the hot items for hikers are. Also (plastic allowed) throw a case of vodka in the closet. Good for many uses, even if it merely makes a neighbor happy.
Not to be a jerk, but a can opener and a cheap camp stove give you vastly more options.