Good to see Epps again, his creepy obsession with Brennan is quite fun.
It's a relief to see that Epps' wife has come to her senses and divorced Epps, got a new boyfriend. Stubbornly refusing to believe Epps would come after her. Boy, was she wrong.
Epps is on a rampage, aimed at Brennan. Angela, Parker, Cam. Though Cam's injuries were her own fault, Zach was asking her to x-ray the head and instead she just went in blind and broke the glass vial. For all her preaching on protocol, she ignored it. Brennan is no better, Epps was going to tell her what poison it was and she taunts him about his mother, making him hang up! It's the problem with poisons, why they could only find the cure once they had the actual poison - once poisons enter the body, the body breaks it down and it becomes near impossible to identify.
A good episode but wasn't perfect because people we know are very good at their jobs start making incredibly stupid mistakes. Epps showing up in Brennan's apartment was also pretty predictable.