Robin has roughly less than a second to recognize that a slurpee and a sword have entered the scene, and both are being wielded by someone who Tim is absolutely not talking to again if he gets shot when Tim already had this. He'll yell at Nico later, though, because right now he's rushing into action to disarm everyone before someone gets shot or stabbed.

"Okay, this is all really unnecessary!" he calls out, hypothetically to the robbers still (like the one whose wrist might have just been broken in the process of removing his gun, but he should have thought about that being bringing a gun into this) but really to the demigod charging with a sword right now.