Can't see anything going wrong in the log... what kind of hardware are you guys on? The game needs ~4 gigs of vram since it has to hold multiple very large images in memory. So an older card might not be able to handle it.
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This one? You only need to trip two of the levers to open each door, find out which ones and leave the girl walking between those.
If you mean the cross-shaped one down and right from this one, that's just about timing, some of the levers stay toggled longer. You should have the girl trip the ones in the vertical section and do the others yourself
Noted, you're not the first one to complain about it either. I'll have to think about ways to further improve it, the player character's hitbox has already been made smaller once if you can believe it.
Oh, the swap feature only works when you have two girls following you, it changes which one you're sending out (with ctrl/right click). But it's no wonder one might find it confusing, it's a mistake on my part to have it displayed in the pause menu before it's even relevant.