Is there any way that I can cause a player to lose by staying in a room for a certain number of turns, (say if they dont complete a task in 5 turns. Such as leaving or whatever.)

You could set a variable to increase in the after turn script for that room. Then set an if statement to check if that variable reaches 5. If it does then make the player lose.

put the checking proc. i the afterturn script.

Hmm yeah you can also time it, in stead of turns...