Kelly: A truce? After everything you did. Trying to steal Dale from me for example? Forget it, I want nothing to do with you. You can go to hell for all I care.

Riley: You sure are proud, but, okay, if you'd rather be my enemy....

Kelly: If you're trying to threaten me, save it too, I'm not afraid of you. Now get out of here once and for all!

Dale can't wait to get out of here, he doesn't want to see Kelly and Riley at each other's throats, things are already complicated as it is. They can't afford to complicate them any further.

Dale: (whispers) Patience, Kel. There are only a few hours left in the dorm, then goodbye, Riley forever.

Kelly seems to have guessed Dale's thoughts, and shares his fears, so she walks away from Riley as soon as she can. Why argue with someone who isn't worth it?