There's only three of us. It's a team, sure, but someone has to step up or nothing will get done.
Achak's CT6 IP2Simple: Observe in Detail to use Motion Sense to get an idea of whether the man is within six meters of the top of the stairs (which is the limit of the Motion Sense power, but should give Achak an indication of whether the man is within ready striking range)
Simple:
wish that he had his Ares Alpha with its flashbangs comm the results to the team and/or comm Elijah asking if he can hack the man's gun
Free: raise an eyebrow at Rebecca
Turning a Simple action into a Free action or two, if that's okay.
Magic 6 + Perception 6:
12d6t5 3 hits, still below average, but the threshold for detecting an average metahuman is only 1 so it should work