Hijack knows that this can’t be enough for them to survive, to fight in a hard battle ahead. He is trying to force them to push on through to show that they have what it takes to keep fighting.

This is now more for his sake as it is for theirs.

Isaac can’t fight because he literally almost killed someone and he can’t handle that again.

Max notice this and takes his stead, because he knows how off Isaac is at the moment.

But Hijack knows that Max is still hurt, so he refuses to fight him in case he is hurt more.