Jenna was, in fact, rather stunned that each heart of the Doctor's beat separately.  Obviously, she's never seen anything like this and she was baffled.<br/><br/>"Oh my!  How?  This is unbelievable! How do they both fit inside your ribcage?  What's the benefit of having two hearts?  Also, what exactly is a Time Lord?"  Jenna took out her stethoscope, and grabbed a second off a metal table, fixed one in each ear and listened to the Doctor's hearts herself, running the cool metal over his chest sporadically, and unintentionally wedging herself between his knees.<br/><br/>"And while I'm asking questions, what could possibly be buried 500 feet underground that a hospital would ever use?"<br/><br/>She shook her head. "But Doctor, you really are absolutely in-ah-a-mazing!"  She caught herself before she said "incredible," feeling impish and adding a smirk.