Even though I hate the military's judgement here, considering in the novel there's a case where an infected students escape much earlier and mutate inside a rescue truck and proceed to bite another soldier, so their superior's order must have change to "shoot on sight". There's too much risk involving rescuing a survivor after that incident and the whole campus area was sealed off for good after that incident.
Though if they really wanted to impose a blockade, they might as well bomb the entire campus area so there's no survivors or infected individuals, effectively burying the whole incident. I'm not agreeing with the military, but this is one of those situation where "small sacrifices for a greater good" type of situation, although it was very much inhumane. If you guys were wondering, there's a group of survivors which escaped the campus much earlier in the story, before the enforcement of the blockade, but some of them was of course already infected, causing a wide spread incidents across the nation.
From the what I understand thus far, this story involves some of the most powerful mythological creatures in Korean culture that is Dokkaebi((Goblin)Easily the most poweful creature amongst other mythological beings) and Kumiho(Nine-Tailed Fox). It also depicted the surface level of Korean Shamanistic belief such as the use of Jangseong(Guardian Spirit Totem Pole) and maybe some deity like Samsin Halmeoni(Grandmother Samsin(Similar to Hariti or Hecate)).
In other similar Korean folklore story, be it BL or not, we've already seen a creatures like Yong(Korean Dragon), Pulgasari/Bulgasari(Metal-Eating Beast), Imugi(Lesser Dragon Serpent-Like Being) and even some important figures like Joseung Saja(Grim Reaper) and Yeomra(King of Underworld).










"Where ride the horsemen, death shall follow." - Chaos Knight.
Above quote actually sums up the reveal of the big bad Primal Fear.