Council of Elrond

Hi, I've a question about PR:
I have in play Gates of Morning.
My opponent plays Preil Returned - this means that GoM desn't work - "it is considered to be out of play"
What will happen, if my opponent plays second PR? Does GoM will be discarded? (becouse in that moment "Gates of Morning is not in play, and Doors of Night is considered to be in play")

Card Gates of Morning will not be affected.
Discarding of resource environment cards (and canceling its effects) is result of resolving the card Doors of Night.
Mere presence of Doors of Night in play does not discard resource environment cards (and does not cancel effects).

Ciachu also had another question and im not sure if iam right. What if i play Peril Returned, Gates are considered to be out of play, and i play another one PR. Do i have "Doors" in play or not?

Then Doors of Night are considered as being in play.