
well the previous comment makes a good point but if i were to brainstorm a reason
the more ppl the harder it is to manage.
they already took in an additional person and regret it. he isnt really helping much, just follows and is scared. at this moment that's not helpful. seeing as he only remember the previous game, its impossible for him to build up a tolerance/ get used to the game making him scared constantly. no to mention since he cant remember stuff, he is basically lurking behind them with a useless map. Altho not his fault, he just holding them back. They have to baby him.
Now imagine this X by the rest of ppl.
the rest of them have their own wired personalities. 2 (not the mc's, the other 2) already have the tendency of separating from the group.
if they were to stick together, they wouldnt be able to get anything done. conflict would happen and it would bring downfall to everyone.

Nah, the author is just going with the whole 'let's get separated' horror trope. Having six brains beats two any day, no matter how hard you try to convince me.
Honestly, no offense if you're into this BL, but it's starting to bum me out. Instead of characters teaming up and using their talents like in Cube 1997 or Danganronpa, we're stuck with this hot mess where most characters are useless. The only one pulling their weight is the Seme because heaven forbid we let other characters grow a bit.

in this story the killer respawns countless times all over the map. they would be wasting energy tbh.
imagine killing one, turning around only to step on a branch which triggers the killer respawn. omg nooooo
but i digress. seems that the only way to beat the game is to collect the items. killing a killer that can respaws randomly endlessly seems like a deadend

thats fair.
tbh it seems like they are slowly leading tho that. they are recruiting characters slowly one by one.
but at the end of the day this is a story. if teaming them up is the end goal, they have to do it in a way that makes sense in the story. they cant just make everyone team up in 2 chapters and beat the game in 4. then why write this whole thing for. you just made a boring story with no real intresting plot. swoop in and out and done. no stakes, no turns, nothing interesting.
its probably coming but has to come at a timing. but yeah //shrug
youre right.
im just sitting back and seeing where its going.

Anotjer thing is that Bada did tried to tell them about this horror thing multiple times and most just goes to hell. Even with Doha and that Hyung help in explanation this time, i doubt they'll believe it 100% and won't be another Hyung that just slow them down. At least to my understanding of their logic.
I dig horror video games and movies, but the author sure loves to play by the book; why not roll with six dudes instead of splitting up every time? Six dudes can totally take down a knife-wielding dude easily. I get there are rules in the game, but at least give the obvious move a shot