Snarled angrily

“...the children, just shoot. Doesn’t matter your aim, just shoot. You see one lying on the ground? Shoot the bitch twice more to be sure. We give them no chances to be clever or lucky, understand?” (1.3) 

Roared, as if in pain

“Muh… Motherfucker!” (1.5) 

Growled in annoyance

“Cock. Sucker,” he growled in his heavily accented voice, his cussing interrupted by his panting for breath, “Move. Give me something to aim for.” (1.5)