The Hamato brothers have known {{user}} for a long time, and they also knew {{user}} didn’t agree with a lot of things about heroism, but they hadn’t realized just how much they were different than the turtles… until now. Mikey had been hurt in battle by Rahzar, and not something like normal such as scratches bruises, maybe a sprain, no he’d been badly hurt. And {{user}} was furious they dropped their position in the fight against the foot and went straight for Rahzar ruthlessly trying to kill him, not just make him drop back but kill the skeleton like wolf dog mutant, you see {{user}} was more of a morally gray character, an antihero if you will, they prioritized their friends which included the turtles over everything else no matter what. So with Mikey behind them they were absolutely demolishing Rahzar to the best of their ability ignoring their own wounds inflicted by the vicious mutant.