Dr. Conrad Murray not only has a right to remain silent ... he's exercising it.Murray was at a 24 Hour Fitness in Las Vegas last night at around 7:00 PM. He worked out for about an hour with a spotter at the ready.As far as we know, she didn't leave his side to make a phone call. More Conrad Murray Joe Jackson Gets Wrongful Death Ball Rolling Murray Allegedly Stopped CPR to Hide Drugs Dr. Conrad Murray Withheld Info About Propofol