@oric212: You get batteries by hitting the tool boxes you find in certain rooms. Unfortunately, the drop rate isn't 100%, so there are instances where you will have no choice but to wait until you get kicked out or just go through a portal (dark room) and still get kicked out.
toolbox is spawned in nearly every room.
after you use it, it may respawn if you wait a little (I recommend using it first).
You are supposed to have enough batteries to move on to the next room. If you wait enough, a doctor will appear. if you aggro it, but NOT KILL IT, nurses will also spawn, and that way you can farm a lot of coins.
IF YOU FIND A ROOM WITH YOUR FRIEND BEING TORTURED, that means you lost, (bad ending) and you went into a room without batteries / you used the potion at the wrong time, in the wrong room.
Lower your graphics to see what is interactable (some boxes suddenly stand out). if you didn't get what you need at first, wait a little but until it respawns. Hover with your mouse around the screen to see what is interactable. Telephone on the wall is your way to quit, never talk to it.
If you find a memo, READ CAREFULLY, 100% it includes an important clue, and sometimes you can't get another one.