Wouldn’t the round arrive before the sound/shock wave ?
Still, I guess it lets you shoot back at the right place if you survive the first one !
If you do not hear the sound you are out of the game.
I have seen a video clip recently of a couple of taliban or whatever, firing a mortar. The clip says that we now have a tool that can track back to the mortar tube after “listening” to as few as three mortar rounds being fired from a single location. These towel heads are filming their actions, and sure enough, as they drop round #4 down the tube an incoming round kills both of them while the camera rolls. Kinda cool!!!