"I'll make it work," Derek assures him, stomping the snow off of his own boots before following Bitty inside, and then he feels a lot of things all at once. He tenses at the mention of the mistletoe, and then of Simon. He hadn't realized that Bitty had already been up here, but all those thoughts are wiped away by the mention of flames.

"He burst into flames?" Derek asks, sounding vaguely panicked as the color drains from his face. It's an instinctual reaction, and he feels a little foolish for it right after. Simon must be fine, somehow, or Bitty certainly wouldn't be here.