Mirror Alex had decided not to cross over for one simple reason: his tattoos. Just before the Queen's announcement, they had given him a warning: PROTECT THOSE CLOSEST TO YOU. He took that to mean he should stay on this side and protect his Queen from any infiltrators from the "Real" side.

So he's patrolling the halls when he sees Gabriel up ahead. Something looks...different about the angel.

"Hey. You cut your hair?"