Hijikata

Ok, so I got my first Nitro RC, the CEN Matrix, it came with the 4.6cc Corsa Engine. Now I've done the 3 idle break in tanks, then started to do my first break in tank, and im drive in it around for a while, engine sputters then shuts off. It sound like it normally did when I was running the idle tanks. I walked up to get my car and noticed my pull start was wrapped around my rear left tire. The ENTIRE rope was pulled out, no idea how it happened. First does anyone have any idea how this could have happened, I drove it around in a parking lot and didnt hit anything. Second is there a way i can fix this from happening in the future??? Also I would like to know if theres an Electric or Roto start for my car and which ones are compatible other than CEN branded ones, if any. The LHS dont carry many CEN products unfortunately. One of the LHS thinks that the Roto start for a Savage will work for my car but before I buy it I would like to know if anyone has tried it and how difficult it was to install (meaning if there were parts that needed to be modified).