It might not be as bad as you would think.
My friend was on an L.A. freeway, cruising along at 60 mph, when her Siberian Husky reached from the back seat, between the front seats, and shoved the gearshift into PARK.
The noise was tremendous, but she shifted back into Drive as quickly as she could react, and headed for her mechanic. He said he couldn't find anything wrong. He said he thought the flywheel (?) was moving fast enough that the teeth couldn't engage.
She drove it for another five or six years before her brother blew the engine out of it.
Sue