Thank you all
Well the title kind of lied --- at the second map you fall down because your "friend" lied to you. It'll be like portal 2,
because your "friend" will talk to you through an old microphone in the entire facility.
A quote from him:
"Why are you coming back? Did you forget your pink purse? Hahaha. Remember that water is really dangerous for you. Have you got the marsh fever? Did you sink your pills? hahahaha, that's soo funny!"
That's the collidecallback if you're coming back in a previous room. Of course it happens only one time.