He made one big strategic error — he should have stayed away from areas where he could encounter large groups of AAs, such as H’burg itself.
While I am all in favor of avoidance, often “wildings”, flash mobs, and State Fair raiders use speed and momentum to make hasty attacks where there are not usually such bands of criminals, and then leave the area.
This can present the additional problem of a mob using a crowd for cover. But that is an added bonus for a knife, because they will have a divided attention, so you can actually go on the offense, involving yourself against the attackers in other attacks.