Derek and Stiles and Scott sort of come together.

Isaac: "So why do we need their help?"
Derek: "Because it's harder to kill than I thought and I still don't know who it is."
Isaac: "And they do?"
Derek: "They might. Which is why I need one of you to get on their good side."
Erica: "Mm. Scott or Stiles?"
Derek: "Either."

Derek tries to reconcile with Scott in his own creepy way he's so good at. Derek knows that he's not strong enough to do this alone. So he tries again, because if Derek is one thing, he's stubborn. When Erica muses over which of the boys she wants to play with Derek looks startled. He knows how much Scott is hung up on Allison. He knows telling Erica to try and seduce Scott at this point would only end badly. Still he doesn't tell her that she should go for Stiles which would be logical then. After a long pause, Derek tells Erica either, but he'd had to think about it. He realizes he'd primed her for sexual manipulation. He doesn´t tell her just to be friendly. Derek here has a certain sexual awareness of Stiles.

Stiles: "You can't tell Derek, okay? There's a lot more to this that you don't know about. And just because you got the Alpha bite makeover doesn't give you a license to go around destroying people."
Erica: "Why not? That's all anybody ever used to do to me. I used to have the worst crush in the world on you. Yeah, you, Stiles. And you never once even noticed me. Exactly how you're not noticing me right now."

Stiles doesn't want Erica to tell Derek about Jackson because he thinks Derek will run off and get someone killed, either himself or Jackson or one of the betas, and I believe that's an unacceptable situation for Stiles. Given what Stiles knows about him, Derek is the kind of failwolf who runs in without a real plan.

Erica had a big crush on Stiles. He didn´t even notice. Because Erica was not pretty enough back then, right? Stiles is a typical boy. He goes only for the one with the looks.

Stiles about Matt: "He´s evil." Stiles is the first who suspects Matt of controlling the kanima. And he is right even though for the wrong reason.

Stiles: "Hey, we need to get her to a hospital."
Erica: "Derek – only to Derek."
Scott: "When we get her to the hospital–"
Erica: "To Derek. To Derek."

Stiles wasn't quite aware what pack really meant. That Erica needs Derek more than she fears her own demons is hard to grasp for the guy who had the luxury to refuse the bite. Now he sees Derek's motivation for making a pack. Before it was all about how much power he could gain, all bravado and intimidation and Derek's slightly offensive you need me to survive life motto. Now it´s about affection and safety and taking care of someone who needs you.

Derek: "Pull her up."
Stiles: "Is she dying?"
Derek: "She might, I– which is why this is gonna hurt."
Stiles: "You broke her arm!"
Derek: "It'll trigger the healing process. I still gotta get the venom out. This is where it's really gonna hurt."

There's panic in Derek´s voice when he's facing the possible loss of one of his wolves and he doesn't really know what he's doing, but he does the best he can think of anyway, because it's better than not doing anything. Stiles is kind of surprised that Derek would break Erica's arm, because despite all the attempted murder and other violence in their lives, Stiles has only just understood that Derek loves Erica and Isaac and Boyd. The fact that he is capable of hurting them is shocking. Derek explains his action in the face of Stiles's outrage. He wants Stiles to understand what he's doing, he wants Stiles to understand that this is necessary pain, not just him being cruel. Derek trusts Stiles in that moment because of their time in the pool. Scott would be more physically suited to holding down a wolf in pain, Scott is also the one Derek wanted for the pack. Stiles on the other hand is the one who rushed in first when Derek said: "Pull her up!" If for the reason to be close to Derek or just being Batman is hard to say. Erica thinks he makes a good batman anyway.

Is there any hate between them? No. Stiles is just pretty shocked by Derek´s action. And Derek is eager to explain himself to Stiles. What about that? I call that progress.

First Stiles still wears the same clothes as in 2/6. Then he wears a green plaid shirt above a grey shirt. Derek wears a khaki longshirt.