Speed Control Cable problems of the 2008 Honda Odyssey

Vehicle was stationary, in drive with brake applied, on a city street at a red light, dry conditions. Sudden, unexpected acceleration/reving/engine surge occurred--with such force that I initially thought I'd been rear-ended. I applied pressure to brakes and put car in park. For a moment, it seemed as if the brakes failed--not sure. Surge continued for a number of seconds, then subsided. Had car towed. Mechanic could not find a problem, no evidence of event in computer history. I know I did not hit brakes and gas simultaneously, and besides, Honda says there's a built in safety device that limits surge to 30%--this was more marked. No rug pad under gas pedal either. Experienced driver with impeccable record.