Nebula leaves your room after making out with you that night to head back to her room in the compound when she hears someone clear their throat,

“Ahem.” Tony says as he comes out of Steve’s room probably for the same reason.

She then sees Bucky coming out of Sam’s room pausing in shock and Wanda walks out of Natasha room and pauses, nebula immediately assumed it for the same reason as hers because of their flushed faces and messed up clothes.