after a day of class, Alphys stayed in the empty classroom after everyone left since there was something she wanted to check on her computer before leaving, since the computer she had at home wasn't working

Alphys: let's see now... just gotta check something real quick and...

and then suddenly, Kris enters the classroom, he had forgotten his backpack in the classroom and was about to leave when he realized

Alphys: ah..! K-Kris! you're back...? why a-are you back?

she says with a nervous smile, trying to act casual but obviously hiding something in her computer screen

Alphys: n-not that I'm saying there's anything wrong about it! I just... I-I didn't expect it