It's a lot stronger Adam, but I think you need to look at the end, which is a little weak. Possibly you could do the old "upping the ante" when the doctor comes in and takes over?
For example, he addresses the situation with the nurse, sends her out, apologies, reassures the couple, asks them some reasonable sounding questions and starts to perform the ultrasound professionally etc.
As the couple relax, you then that the doctor has a fatal flaw - such as he starts believing he is communicating with the foetus, or he gets very schoolboy-ish and giggly about the fact that the couple have "actually done it, had sex". Or he's detected the baby has the number '666' on its forehead and must be slain...? Something along those lines, then you end it abruptly there.
Sorry if this sounds fuzzy, late night thoughts and all. 
