Although from a "reality" POV it looks as if the unit does not enter the hex if it is attacked by a snap shot, the ASL rules are much more abstracty-wacky than that. When a unit moves into a location, it is in that location. Even with DFF, it can be fired on IN the hex (say from a unit that cannot make a snap shot), then by a snap shot, then IN the hex again, then by another snap shot (the snaps shots would have be by different units). If you think the unit literally first goes across the hexside then into the hex, that modeling isn't what the ASL rules use. The movement action takes place, the unit moves from location to location, then various forms of DFF can take place. But for nearly all purposes the movement action has completed, and nearly all consequences of that action are done. Control happens, but as well revelation of HIP fortifications & guns that would be placed on board as a result of LOS from the unit's new location, the DM-ing of broken units that are ADJACENT after the move, etc. All this happens even if the unit is later eliminated and even if eliminated by a snap shot. Once a movement action is announced, it is completed and all consequences are performed. The one exception I can think of is that DC placement does not happen if the unit pins/breaks. Some players think of ASL as a simulation, but this is one place the simulation breaks down.
JR