Prompto and Pancakes both looked up from the knock at the door, where they were engaged in playing with a feather on a stick (man, but this cat had a stupid amount of toys), and he glanced over for a moment to where Nina was working and figured he'd take on door duty so she didn't need to be more interrupted than she already was by him even being there in the first place, tossed the toy for Pancakes to go chasing after it, then hopped up to his feet to answer it.

"Summer's not he--" he started, as he opened the door, which was an interesitng greeting if you thought about it, because it definitely opened up a lot of questions on what he was doing in her apartment when she wasn't even there, but then he saw who it was and the words halted right there. "Oh. Uh, hey, Liam. You're, uh, probably here for Nina, right?"

So he stepped back, opening the door and gesturing an invitation with his arm as if this was his own apartment or something.

Look, it's not like Summer didn't know, or something!