I don't understand how Data's suggestion could even work at all. The air being forced out of the airlock is not pushing against anything; it's moving into hard vacuum, right? So it's not the same as (for example) a blown-up balloon that you release without tying, where the air escaping has other air to press against.
Newton's third law of motion.The Enterprise is expelling matter aft, this is where the propulsion forward is coming from.
I'm not exactly sure what the dimensions of the main shuttle bay door is, but assuming that there is sea level pressure in the flight deck, initially there would be over six thousand tons of force.
The air being expelled from a balloon doesn't push against the air in the room moving the balloon forward. The reaction force is pushing against the "inside top" of the balloon, as the air exits the "bottom," this
moves the balloon forward.