can someone spoil duty after school webtoon's ending for me

i just finished the kdrama and it actually made me turn off my laptop and go outside for a walk because what the hell do u mean they survived months of combat and killing little aliens only to die from a nerd with a gun??? and what happened to wonbin???

is the webtoon different? i'm thinking about reading it if it has a better ending but im curious on how different it'd be.