Window open ahead of time = foreknowledge.

Window open before assumed breech of room = foreknowledge of tactics/threat level

Acting with enough time to pull this off = agents own alarm was tripped (down the hallway?)

Flashbang = catch agent alive.

Takes one to know one.

Imagine standing in fear as the very intelligence community that trained you is now organized to take you out…

Some don't have to imagine.

Sweet dreams.