He isn't sure what Reid's being so insecure about. They're both guys and honestly they've seen it before on several occasions where the circumstances were pretty dire, like when Reid had to be sterilized when he was infected with a virus and Derek wouldn't leave him alone. But then he says he's Euphie, and Derek gets that it's a curse. Someone he's protective of is swapped with someone else he's protective of which makes the big brother-ness in him magnify tenfold.

"Euphie? Look... it's okay. What? I mean..." He pauses to take a breath. "It's a curse... I think."