The 'sniff' at the end sounds to me like something is being swung around fast.
Also, I can't hear much of a difference between the Angels feet and the other feet running at the end. But that doesn't say much cause cause the alarm is covering Angel running out.
A final thing I noticed re-listening to this is that the alarm has faded out/stopped before the last shot. If it has stopped could this mean that Angel is resetting the alarm while the shooter is still in the room, thus ruling him out?