The person who walks through the door is definitely not concerned about the it.
"Hello."
"H-hi Susie." The dinosaur-esque person who walks through the door has Alphys scared.
"Am i late?" Susie asks with an uninterested tone.
"N-no, not at all! A-actually, we were just g-getting started." She starts looking around for something. "H-has anyone seen the chalk?" She looks around and sees (almost all) of our unsurprised expressions.
"C-come on. This is the third time this month this has happened, and you know I can't start class without some." No looks change. "Alright, how about this. If no one speaks up, everyone gets in trouble!"
Alphys looks nervously at Susie. "A-anyone?"
Not wanting to get in trouble, i try to say something.
"Are you sure you don't have any extra? Maybe in a supply closet?"
"G-great idea! Susie, can you go get some from the supply closet?"
"...whatever." Another door slam.
"Excuse me kid, but I need you to go and make sure Susie gets the chalk. Kris, go with them too."
After a few "good lucks" from the class, Me and Kris head out the classroom door, ready to face Susie.