Of course he was really mad. What did she expect? Had she not seen the aftermath of his and Marty's fight before? Had she not heard about 'the two gorillas fighting' or whatever? Clearly Taisce didn't think this through very well. This was going to likely piss him off more than anything.
He frowned. Why was she being so calm? He lifted his chin a bit skeptically, "you can't see into the tower from down below. How'd you know he wasn't sitting down?"
O'Brien looked around, after grabbing up the walkie talkie, "sure, you say that, but he's a fucking bastard. Let him or not-" okay, so he was talking over Taisce, and her trying to tell him that she already let the others know, and that was when Marty came waltzing back into the tower.
Glaring across at his former partner, he tossed the walkie onto the desk as he took the few steps it took to cross to Higgins, and grabbed him up by the collar to shove him back against the doorframe, "I told you not to mess up, Higgins. Do you know how many lives could have been lost if you weren't here, at the main guard tower, to notify everyone that one of those mutant zombies was approaching??" He pulled Marty away from the door frame just enough to shove him back against it, to emphasize his words, "Do you??"
He turned Marty, and grabbed him by the back of the shirt to start pushing him back down the stairs, "I told you if you fucked up, I was going to A, either lock your ass back up in a prison cell, or B, throw you back outside the prison walls with your dog. And since I'm feeling particularly nice today--" he began through gritted teeth, "i'm going to let you choose. And then I'll figure out where to go from there, how's that?"
Half dragging and half shoving Marty back down the stairs to the prison yard, O'Brien had practically forgotten that Taisce had been watching him be a complete bully to Higgins. But the bastard deserved it. O'Brien had straight up told him how it was going to be if he stayed. And as long as he didn't fuck up, they'd be alright. But leaving your post? That was not okay with O'Brien.