Susan heard Regan's footsteps drawing closer as she tried to quickly finish the letter. The Slytherin comment on her letter, making it sound as though Susan was being slow. But, of course, she had been waiting for a few minutes now, Regan was the one who was dawdling.
"Of course," she replied. "I was just waiting." She folded the letter and tucked it into the pocket of her robes. Straightening herself up she looked over at Regan.