According to 220.127.116.11.10 vehicles may freely pass through opposing vehicles but may never end their movement in the same hex.
Assume that a vehicle passes through a hex with an enemy vehicle and it has already expended half or more of its movement points. An enemy vehicle with OW fires and damages the friendly vehicle. According to 18.104.22.168.6 it has immediately it's remaining speed allowance reduced by 1/2 and so it must stop in that hex. What happens now?