Each army has different styles of fighting depending on the styles of their generals. So their soldiers also developed different habits because they were already accustomed to it as they had executed a lot of things based on those orders.
So Mervin also couldn't interfere with it, so he only had to do his best to put them in an area where it suited them best.
Well, at least because the army that came was the 7th army which was already stationed on their west side for two years.
Most of the time the ninth army was the one to bear the brunt of the attacks from the zergs, that's why those in the east and west region nearby were already accustomed to assisting them when there were a lot of zergs to deal with.
So at least their cooperation in coordination and dispatch of soldiers was already good.
