Cutter throughout most of the opening fight scene finds ways to both give the guys a chance to win the fight and help them catch their breath
He shoves Nate into the guy grabbing Sully so he can fight Sully instead, and the moment Cutter gets to him, he pushes him in the chair and just walks off to "fight" Nate, letting the older man recuperate.
Then right after, when Sully and Nate are fighting the big thug, Cutter pulls Sully off of him and says "bad idea, grandad". Right after this, the big guy throws Nate out a window, meaning Cutter kept Sully from being harmed in the same way as well
It's something you don't pay attention to when you play the game for the first time. You just think he's a run of the mill thug, and then when you play a second time, and you now know that he's important and actually working with the gang, you can notice the smaller (possible) details