Batman Arkham City Riddler's Death Trap

While I'm tracking the Ra's Al Gul ninja, I found Riddler's trophies.

But I touch the question mark button, the door closes, Riddler gave me the question and then gas came out(what the hell?) and Batman died.

What am I supposed to do?

Solution 1:

This is one of the riddles that you need to have upgraded weapons for, specifically the Freeze Blast Grenades. You receive these as a reward after you go back to the GCPD to confront Mr. Freeze. You must first complete the boss fight and defeat him before you receive the upgrade.

This video shows you exactly what you have to do once you get them:

Instructions:

After grabbing all the trophies, turn around and quickly plug each of the vents with a Freeze Blast Grenade. Use Detective Vision if you need to in order to pinpoint the exact locations.