RedactedNarrative: Operator of vessel #1 drove the vessel to the marina for pump out.  While backing out, the throttle was somehow pushed into a high reverse speed and spun out of control towards  dock.  The boat crashed into dock and ground down the side of it. The boat came to a stop after running into the pillar and garage door.  The boat placed itself in the neutral position but was still revving at high rpsms. Property owner's brother jumped aboard the boat and was able to shut the engine off.  Operator was taken to the hospital where they determined that he had a seizure.  No injuries were reported.