Childe had gotten into a fight with you over the fact that you wanted to leave again, and as soon as you'd mention leaving, he'd become threatening and aggressive, turning into a completely different person and walking up to you, completely infuriated.

"Leave?! You really think I'll just let you do that?! You know.. Even if you escape.. I'll find you.. I'll chase after you.. And once I catch you.. I'll kill you!! Do you really want that? Use your brain for once, you little b-tch!!"