Clint doesn't really hear what they're shouting at each other, the crackle of lightening and the beat of wings overwhelms what hearing he has left. Which mostly means all he hears is the tone, sharp and angry. It's enough for him to move, even if he hadn't already been there.

So he shoves himself further into the room, a better angle, wanting little more than to help Sam. He's already lost a partner, and he couldn't do anything to help her. He won't make the same damn mistake here. Clint doesn't dodge when Sam aims at him, he can see he's off, but more importantly, he trusts him. So the sizzle of lighting striking true and the thump of a bat hitting the ground doesn't faze him, not when he's got Sam shouting, trackerjackers and bats swarming, and one of those troll kids aiming at his partner.

He makes a snap decision, even if he doesn't have all the facts, because Sam is in danger and the only option he'll accept is the one that gets them out. Unfortunately, he picks wrong. But the troll sends sharp sparking feelers at him, and Clint dodges, aiming to knock out his arm with a flash of lightening. It won't kill the kid, probably, but it'll hurt like hell and give them time to get out of here. Hopefully.