The next couple of seconds seemed to pass before Sinead really had a chance to get her head around it, still too bemused by the whole situation. House elves were seriously weird- but okay, Professor Newton seemed to have taken care of that. And the portrait was talking to her, and now another Professor Newton was here, and how would they know which one she was talking to-

Glancing between the portrait and the teachers with an increasing frown, Sinead settled for a quick "Good afternoon, Professor," to her History of Magic teacher, before looking back at the rather irritable portrait who seemed to consider her his personal attendant. Still, fair was fair.
"Scourgify," she murmured, passing her wand around the frame and leaving it nice and shiny clean gold again. Except for that bit in the corner. Oops.

Once this incriminating evidence had been hastily scrubbed away with a tissue from her pocket, she glanced back at the teachers, neither of whom seemed to be able to provide a very satisfactory explanation for Flynn's absence.
"Why doesn't somebody just ask him why he isn't working?" she asked with blunt logic, looking between the two of them. Really- it was his job, and he couldn't have literally disappeared, could he? Somebody must know where he was. Maybe just in bed, if he was ill like Tinka said.