How can you give the ball away in that position, and not even have the desire to chase it? He wouldn't have been tired, either, as he was only on ~10-15 minutes.
Did the same when running the ball out from the back only a few minutes earlier. Rush of blood to the head when they pulled the goal back. Wenger did a horrific job keeping them on the right mental track throughout the game. When they conceded they lost their patience, their passing game went to shit when they needed five minutes to get their foot on the ball and get comfy.. and then when they scored, they went mental like hamsters on acid.