"Defend the Citizen" is an objective during the mission On Johnson's Trail during Sequence 6
Optional Objective
Stay below Notoriety level 2
Walkthrough
You have something of a tricky engagement here. There are 4 Soldiers that need to be dealt with. Engage them quickly and take them down swiftly. This will ensure that you cannot gain too much notoriety. The swifter the victory, the less likely you are to gain notoriety. After enjoy the cutscene and then Connor is off again to meet with Sam Adams.
