Why are they in freefall walking around on the top of NX-01's saucer when there's gravity plating just a few feet below them? What is it with SF shows and movies that they think ship hulls could somehow be opaque to gravity (or that gravity is like sound and only works in an atmosphere)?
We don't really know how artificial gravity works in the STAR TREK Universe. If we accept the "grav deckplate" model, then perhaps it is possible the ship's outer hull would be "out of range". In other words, when Mirror-Commander Archer ordered Mirror-T'Pol to increase the gravity on the Defiant's deck in ENT's "In a Mirror, Darkly", perhaps the effect is localized from the floor to the ceiling and not beyond. This would mean that anyone still looking for the Gorn on the next deck up would not be affected.