What was that sound?

A few weeks ago, we were in anatomy lab, looking at the skull and brain. Since we've already dissected all the muscles of the body last year, our dog is not really in one piece on her left side. The left limbs are pretty butchered and I think they're both unattached from the body. Since we were looking at the skull, we wanted her flat on her stomach, not lying on one side, and in order for her to lie flat we had to dangle her right legs off the edge of the table. Otherwise, the right legs would prop her up, but there wouldn't be left legs to do the same, and the cadavre would lean sideways.

At one point, we're foiled by some structure or other, and all five of us gather around a large poster nearby to see if we could match what we were seeing to the diagram. While our backs are turned, we hear an odd shthlap! 

We look back, and our table is curiously missing a dog. Out of the entire lab period, the cadavre decided to be unbalanced and fall off right at that moment. Fortunately, none of the faculty were nearby, or we probably would have gotten another lecture on the happy, tail-wagging dogs.