Video: Bystander Pulls Knife on 'Dr. 90210' StarDr. Robert Rey has plenty of experience taking blades to chests as a plastic surgeon on 'Dr. 90210,' but in a disturbing incident outside L.A. hotspot Roxbury, the doctor was almost on the receiving end of the knife.

While TMZ cameras rolled, a tattooed partygoer told Rey he wasn't digging his ultra-tight, pec-bearing shirt, jocularly saying, "I hate his outfit."

Rey quickly lost his sense of humor about the situation, telling the man, "F**k you, motherf**ker. Can you back that up?" to which the instigator responded, "Damn right I can, homie," while pulling out a switchblade.

A fellow clubgoer quickly intervened, while Rey asked the cameramen, "Where are the police when you need them?"

Check out the video.