The oxygen bit... oh you had me going for a minute. Bravo XD I've been enjoying your sense of humor.
Where do I find the chef who'll give me a pizza? I swear I've searched those kitchens top to bottom.
Also, I have been unable to complete the blue bottle quest. I'm pretty sure I know which storeroom it's talking about, but it's blocked by trash I can't seem to interact with.
Glad you liked that bit, had to make those sprites for a 30 second joke xD.
The pizza can be found in the buffet area of the cafeteria, not in the kitchens.
And the blue bottles are in the storage room right next to the one you're thinking. It's a room with a lot of shelves. The door that's blocked by trash is inaccessible.