Yep, you right. Red doors only passable for Kana. Red carpet is her route. Keep in mind she also uses elevators. And maps in hospital are pickable only by Kana
Not like you have to wait or anything.
Just rush to the boss door, hit the blue vortex & kill the boss. If you're not trying to get spy cameras to pick up some shenanigans, you can get in 'n out real fast.
I replayed those things dozens of times before I got that those parts are just on an infinite loop and don't even offer all that much EXP to begin with.
Though levels really don't offer much gains, the elite monster drops however do. Towards the end I found out I had a +64 frost gem.
Dunno which dungeon or which monster, but I got it. That alone did more for my stats then +12 hours of painfully boring grind.
Though, going off my playthrough, trying to use the spy cams is a scam. I only ever got the same 3 scenes out of dozens of times I caught them. So it was NOT worth the wasted time constantly waiting in the monitor room.
Then again, I only ever kept getting the same few basic scenes in the night time too, so meh.