Kat in the boiler room

Was there any significance to the brief scene of Kat (I assume it was Kat) doing that weird bowing thing on the ground of the boiler room when Rose was peeking through the window? There wasn't really an adequate explanation for why she was contorting herself in this scene and the one when she was in bed under the covers. It just seemed like an exorcist rip-off that was thrown in for shock value.

As far as the film goes, the director was quite good at setting a creepy atmosphere of dread, and in hindsight the story is better than first appears. Despite these pluses I feel that the pace was too slow and the script could have fleshed out the characters more and helped the viewer understand their motivations better. I'd give the movie as a whole a 7/10, and am confident that we we will see even better things from this rookie director in the future.