Have someone take the blue liquid and quickly but quietly and unseen, sneak behind that table with a chair and mirror.
14
Then, if the person fails to sneak up without being detected, have the team pop out and hold the armored guy at gun point, but if the person does make it without being seen, have the team listen for a tiny bit longer, and have the person get ready to move again.
I'll let everyone else decides who moves up.