Thanks so much for playing and for the feedback. greatly appreciated!
There actually is a third icon that appears during the 4th sequence for a few rooms before vanishing. :)
Although I realised since that I should have done a better job of drawing attention to it. Maybe using a lights out moment like in the 3rd sequence to make the player focus on the monitor, or some other environmental indicators.
Fully agree about the restricted doors. Might be something I include in a future update.