The cops. Of course.
"You're going to have some explaining to do." Maelstrom said, and manipulating the air around him, sailed out of the door at full speed. As soon as he was out, he flew straight up. Any one nearby would have felt short of breath, from the vacuum created by sending so much air into the sky.
It was the perfect plan. No one dressed in black was ever a good guy, and the smell of everything in the bar probably wouldn't help his case. Eventually he would probably be fine, but having the nearest hero spending his evening in questioning sure would help Maelstrom make a clean get away.