The velocity of a mortar shell isn't that fast, so if you can hear a long, drawn-out whistling sound, you'd better pay attention because the shell will fall near you.
Andrew ran forward at a speed unmatched by his size, then squatted behind a large plastic barrel filled with sand, waiting for the mortar to explode on the roof above. Once it did, he stood up and said to Li Yang, "Come on, we'll talk here."
Gao Yuan and the others were all in a hangar that could accommodate at least a hundred people, and it was covered with about two meters of sand. For bunker-busting bombs, such a temporary hangar is completely useless, but this was Afghan, and the Afghans didn't have bunker busters, at most they had artillery shells.
As for mortars, there was no need to worry at all, so Li Yang didn't have to worry about Gao Yuan in the hangar next door.
"Whatever you want to say, now you can start, but I suggest you make it quick."