While merging onto the freeway, the accelerator pedal got stuck to the floor with the throttle wide open. The brakes and emergency brake were ineffective. Measures had to be taken to drive off of the road into ice plant, we we were able to turn off the engine. Further inspection revealed a missing grommet at the wall where the throttle cable passes through to connect to the gas pedal. Furthermore, the plastic around the throttle cable was cracked, which allows for the throttle cable and pedal to push through and get snagged. This could have ended horrifically. We are lucky to be alive.