It’s a new deathlike room with a delayed effect!
At the beginning it’s a sort of safe room as nothing happens inside it, but, once this room is activated and the Exit Room is activated too…several death rays will start moving inside the room causing the death of whoever is or enters inside it…an instantly death room!
p.s. With “activated” we mean that both those rooms are opened, it doesn’t matter if somebody is or not inside them…