[Luckily, Asriel does stop before he's out the door. And the realization sinks in before Asriel tries to reassure him that he won't be gone long.]

Oh that's right... I completely forgot I can't use fire magic anymore.

[But if he can't use a stove, now what? Asriel doesn't know how to help. Mom's not here to help. He's so frustrated at himself that he can't even help his friend.]

I'm... I'm sorry, Mettaton. I'm not really sure how to fix this. Mom knows a lot more about this kind of stuff than I do...