Why were there just a few SANS Units defending that position? That's because of CAU55TW8's group, where Celis and Kentucky were present. They made it so much harder for the SANS Units to attack them, and they kept that defensive battle formation while they slowly approached the city's barrier ahead.
Because of that, the certainty the SANS Units had that Qwerty was in that group increased more and more. Thus, the many SANS Units that were still behind the barrier moved, stopping right behind where CAU55TW8's group would attack the barrier. If they opened a hole in the barrier and CAU55TW8's group entered, the SANS Units would all be there to intercept them.
That, however, caused the SANS Units in the surroundings to pretty much disappear, and that's what Roan planned. Celis and Kentucky's Domains were perfect to catch the SANS Units' attention, especially if they pretended they wanted to enter the city by forcing their way forward.
