I am fairly certain that that is mathematically impossible. 16 * 4 = 64.
Infantry models have 80 HP.
It might be impossible or not but it happens sometimes when they snipe, maybe that's what some people call it RNG. It was not a while ago when I was watching Lenny's stream when he was playing as axis and at his first engagement one of his models got sniped by the Soviet combat engineers and he exactly said: "I wish my engineers could snipe like that" not sure if he still remembers that!