this scene establishes a really excellent dynamic between stiles and derek— without derek even being there! both stiles and derek are seeking to fill a particular role in scott’s life: some sort of mix between mentor and brother. in season one, it’s established that scott is stiles’s only close friend. at the time of this episode, scott is also the only werewolf in beacon hills other than derek and the alpha. scott is the thing that connects stiles and derek; without him, these two characters would likely never interact because stiles would need nothing from derek and derek would need nothing from stiles. however, scott can sometimes be pretty impractical, and he needs the pragmatism that characters like stiles and derek can bring to the table.
what’s particularly interesting here is that stiles is outright acknowledging the competition between him and derek to fill this important role in scott’s life. it comes off like a joke, but stiles wants so badly to best derek at being scott’s “yoda” that he works with scott through his anger over the events of the tell [1x05] (before he forgives him!) in order to be the person who helps scott find his anchor.
here, in heart monitor (1x06), stiles holds a lot of animosity towards derek. however, between this time and the end of season two, he and derek are forced into several positions in which they have to rely on one another to save themselves or scott. finally, come fury (2x10), stiles seems comfortable enough to simply accept being paralyzed on top of derek— even if it is a “well, what can you do?” or “bigger
lizardsfish to fry” sort of scenario— and derek reveals some very interesting, new (though vague) information to stiles about the balance of the universe, which is particularly significant because derek is characterized by not really sharing information with… uh… anyone.
but derek and stiles are an even match. they’ve been connected since derek first implored stiles to keep scott off the lacrosse field in second chance at first line (1x02). regardless of whether or not you ship sterek, all evidence points to these two characters continuing to team up to protect scott, eventually allowing what’s left of the animosity between them to evaporate completely.