I'm surprised no one in the friends group told Gi-hun his plan sucked

I mean "let's overpower armed guards, use their guns and spare ammo to engage unknown number of enemies in close quarters in an unknown environment, with a strong possibility that they've already had contingency plans for such attempts" does sound like a plan proposed by an obsessive degenerate gambler with overly inflated ego and self-righteousness.

I'm just surprised none in his friend group, including Marine and special force veterans, told him how dumb this idea is.