The attempt to block connected but Sasuke might have ignored what the interloper said altogether and simply dodged around him and his weapon were it not for the fact that, quite abruptly, he started speaking in a tongue Sasuke had never heard before. Was it a curse? Some kind of attack? Sasuke recognised the lift of a question at the end of it, but why the hell would he be bothering with dialogue if he wasn't going to speak a language anyone understood?

Muraki continued to speak recognisably, at least, but he also moved again -- with clear deliberateness -- and Sasuke swore at the idiot, minion or misguided white knight or neither. With a movement that was nearly lost to visibility in the dim light, he dropped his sword low and swept it upwards, trying to clear the other patient's defending weapon and slip under his guard towards the real threat.

"He's in league with the fucking Institute, you blind fool," the curse biting out with a harshness Sasuke rarely allowed with anyone who (didn't matter as much as) wasn't Itachi, who wasn't Uchiha -- and the irony entirely lost on himself in the heat of the moment. "Make another move and I'll cut you down where you stand, Muraki."