I keep seeing that “At the moment, nothing” line turned into something romantic or Magnus being the best boyfriend ever (bc he’s so worried about Alec that’s why he’s upset etc) and…I mean he is worried absolutely, but full stop Magnus is allowed to be imperfect and human and that means despite understanding why Alec is freaking out and yelling at him, he can still find it all just too much and slam down those walls – his instinctive reaction whenever he’s emotionally stressed or wounded.
Like, Magnus has a heart he’s guarded fiercely for over a century. His refusal to let Alec risk his life isn’t just about it being for Alec’s sake. It’s also about Magnus because he’s falling in love with him, he only just got him, and he’s really not ready to watch a man he’d hoped would end his 100+ years of being lonely and unloved throw himself into the fire 48 hours later. And yeah, that’s a little selfish but also it’s okay for him to be selfish.