My 2 cents.... There are a dozen quotes I can't quote them all so I will summarize. Please bare with me. The primary security for the whole tower was that front door lock. Angel was angry Michael shot out that lock. There was every possibility that Michael could have fallen at the front door with Tod and Lizzie leaving the main door upstairs which was not the strongest door open and inviting any zombie that felt the desire to walk up stairs for a late night snack. He (angel) is at this point not prepared to lead. I like the term.. Riker to Picard.. Michael is the leader the tower needs at this stage in the game. He is tried and tested by war. He is a front line solder a leader of men in the face of combat. HE stinks of leadership and confidence. Angel as a butter bar LT.. does not. But he is learning from Michael. When and IF they survive and get out of LA to some place else a place were a semi normal civilization can be established.. Then it changes. But for now.. Michael is it leader.