The advice from tigerhonecker is excellent.Automakers are aware that folks are going to drive with the emergency brake on-happens all the time.If it were a big problem because of the electric motor they would have put an "owner proofing" device on it to prevent motor engagement with the EB on.
I once drove a Dodge Minivan-a rental-about 70 miles-at 70 miles per hour- with the EB on.When I noticed it-I got out,and there was a funny burnt smell(no kidding),but I drove it another 1100 miles-no problems.Luck,Charlie
PS-I was glad it was a rental!!