He squeezes his eyes shut, trying to find a means of filtering enough out that he can hear himself think. There has to be a trick to it, as there was with Dale -- he found if he focused inwards on his own heartbeat, everything else became white noise -- or Matt would have been insane a long time ago for how overwhelming the noise in his head is. And maybe that's it, maybe that's why he thought it was a good idea to try to steal Mohinder's memories, maybe he was insane. He certainly feels like he's getting there, himself, and he's only had this power for a minute or two.