Board Thread:General Discussion/@comment-11239531-20190705235528/@comment-26907577-20190706001205

IIRC, Alphys evacuated the monsters "somewhere safe". This is implied nut never confirmed to be the True Lab. As for your experience, there's a simple and obvious explanation: The True Lab never checks what route you're on, because you need to hack to not be on Pacifist. When you're ejected into New Home, you're back on a normal genocide because the Asgore encounter does check what route you're on.