If anything, the professor (http://tvtropes.org/pmwiki/pmwiki.php/Main/TheProfessor) looked even more flustered than Katie did.  "Er -- nonsense, no harm done, no apology necessary."  He smiled nervously, fumbled with his unlit pipe, blushed slightly, and attempted to back away.  "I, ah, um, yes, was just on my way out."  He turned and immediately banged into a shelf full of various ointments and then staggered backwards into the shelf of lubes, all making a horrendous clatter.  His got significantly redder and dropped his pipe.  His eyes widened and he knelt down to pick it up, banging his head against the shelf again. (http://tvtropes.org/pmwiki/pmwiki.php/Main/AbsentMindedProfessor)