wow, this was a brilliant episode. Doctor Temperance Brennan realized through the eyes of a victim that she was shutting herself off from her friends, her co-workers and the rest of the world and that she made a gigantic mistake by not getting romantically involved with Booth.
I was by the way half-expecting that that security nightguard was also a figment of her own imagination, or someone who died a long time ago and was helping her in a "sixth sense" (you know, the movie with Bruce Willis) type of way :P
Really an excellent episode! This show keeps getting better and better!