Benjamin used the water element sensing technique the entire time he was following the patrol guards.
If this was a trick to capture and kill mages, then later he would definitely be facing something that could restrain magic. Even though Benjamin thought that his act was so perfect that even the patrol guards could not tell who he really was, but who knows what could happen?
Maybe the order the guards got was to get anyone who enters the division building to the designated area by hook or by crook. And after use whatever methods specifically targeted at mages to get rid of them quietly.
Benjamin didn’t think that he would be gotten rid of, but there was no harm in being a little more careful.
He had a thought that they might not be going to see the governor of the city.
