Ok, so, at the end of the level, there is a jumping section with beds and a green barrel which releases a green token.
Is this token what grants you access to the electric switch on the upper right corner of the room?

I always miss reaching the token before it disappears, and given how slightly imprecise the game can be, I'm very much afraid of possible timed jumping puzzles.

I tried checking a video guide on youtube, but the only guy who posted footage of this game plays with God Mode on, so he walks away unscathed even if he screws up big time...

I know I could abuse god mode to finish the level, but I'd like to see if I can do it legit, seems just more fun to me.

I'm having this exact problem, and the only video I could find on Youtube was the guy playing in god mode... haha
Yeah I am totally stumped and stuck on that level. I would be real happy to figure out the solution. I'm hoping you don't have to grab that green coin.

I figured it out! It's a secret door.

At the far end of the Surgery room is a door that opens a closet, one with a hanger, the kind you typically see goodies in. This is a secretly enterable! Just push up and he'll step through as if a portal door. A laser deactivation switch is in the next room. Besides that, all you need is the hypo needle from the floating bed rooms to KO the guard.

very interesting. I had trouble with dave and haunted mansion, the first level you try to get into a gate, but its locked. i figured out you have to jump on the tree in order to jump over the gate. was an easy one to figure out for most people, i took a little bit to get it.