The Emp doesnt really care about anyone.
He tells them what they want to hear. So they will fight harder, and will throw anyone in front of the spear to survive, including his golden sons.
Any gate left unguarded will eventually fall and it was a siege. Im guessing they ran out of psykers, while the Emps was still on the Vengeful Spirit. So Malc jumped on it.
If 1k brought him 24 hours. Max slots was 10k.