Small and possibly meaningless Iron Lung realization.
Every time I've watched this movie, I've been so confused about why Ava asks him if he's sure it's a skeleton. Like yeah, what else would it be? It just hit me that she's obviously aware of the X-ray camera and what she's asking isn't: "Are you sure it was a skeleton and not X." It's: "Are you sure that thing isn't *alive?"*
This has absolutely no bearing on the rest of the plot, it's just me realizing something that everyone else probably got the first time lol.