Sherlock can't help but smirk a little when his friend agrees that out of him and Bill, the obvious superior force is him. He likes being superior. Unlike John's torn role of half leadership, half duty follower; Sherlock is entirely leader in terms of how he handles things. He's never liked authority figures and he only follows the rules when they suit him. He's had a history of taking law into his own hands on several occasions, either by letting criminals go when he finds their circumstance and crimes not worth the punishment they would receive as well as intentionally adding discomfort and harm to those he believes deserve harsher punishment. (Irene Adler and Operative Neilson, respectively.)

Unfortunately, he's late to the game and the group has already established dynamics and someone who questions authority doesn't quite belong. Either the group will adapt to him or he will be forced to go on his merry way like Bill is pining for.

"And you're worried about how the rest of the group will react to what's happened," Sherlock predicts as he looks down at the back of his friend's head.

"I don't plan on pressing charges or trying to convince people to choose sides. As far as I'm concerned, it's over. He doesn't matter," Sherlock tells his friend. When he'd gotten those few blows in, he'd gotten over the deliberate miscommunication. And when Bill struck John, he felt like he'd taught the man a lesson that couldn't be conveyed in words. He's not the type to hold grudges except in rare circumstance. But, if he catches Bill trying to hurt John through him again, he will retaliate.