Why do soldiers camouflage their faces in the movie Train to Busan

(1)But why did zombies go to Busan because they are sensitive to sound
(2)4 Quark B
(3)The executive told me to do it
(4)You’re Deathfield B
(5)Answer – dc App
(6)→ a pure child
(7)LOL. LOL
(8)4 Universe
(9)wtfLOL. LOL