That's Impossible, Even for a Computer

'''That's Impossible. Even for a...''' is a challenge that takes place in Lynchwood. In the South-western part of the map, on the side of a large building there is exhaust pipe. Each few seconds the hatch on pipe will open, and burst of fire will come from it. Player must throw a grenade into the opened pipe to complete the challenge.

Around the exhaust pipe there are four light bulbs that will light up red one by one, as the hatch is about to open up.