I think the suicide vest was a sham designed to give the murderer time to aim.
“Don’t attack me or I’ll set off this bomb! In the meantime, let me fire some more rounds into people.”
It is a strategy that must be overcome.
It can be overcome with a bucket of water.
If he’s dead he cant set off anything..
Looks like it worked. The police held off entering the building for 15-20 minutes, according to the Washington Post.