Run left all the way back to the original compartment (more scary time; hit spacebar like crazy when the tentacles get close) and find the box. Put the key in and turn it several times.
Now there doesn’t seem to be anything else to do except pick up some more litter, then sit down. Look down at your legs. Eeek!
I guess it’s to be continued some more?
Scary time: hit spacebar like crazy when the “panic” button shows up.
You’re now in a different compartment. I get a bit hazy here, but basically you pick up trash until you get a bottle of cola and some mentos. Combine and use on the encroaching black fog. There are red eyes that show up in the fog, aim at them. If you survive, go to the very right (but stop before you hit the monster in the wall) and get the key from the seat.
There’s a mirror behind one of the signs above your head. Use it to look inside the vent (also above you) and get the metal object. There’s another similar metal object on the floor somewhere, get it too.
Go to the end of the compartment. Get the paper with the lemony spot and the chewing gum from the left seat; I believe the matches are in the bag to the left. There’s also a box in the bag; put the metal objects (lock tumblers) into its lid. Light the candle and use it to read the lemony spot. That’s the code to open the box.