Freaky Friday

AYLA: While we were at the V-E-T the other day, I saw something rather scary.  I mean, aside from the temperature thingie and the needles.

 There was this picture on the wall showing our insides.  I got to thinkin about that.

How did the Beins find out what we looked like on the insides?  I can only think of ONE way.  An that freaked me out a bit!