His armor is failing to protect his vitals. Yes, his heart and head are covered, but there's nothing to prevent a wolf from slashing open his stomach and having his intestines pouring out all over the ground. Gut wounds are often fatal in modern times, even the small puncture wounds cause the shit/bacteria in the intestines causes infections rapidly. Not to mention how soft/squishy you are there, unlike the rib cage protecting the heart and lungs, there are no bones protecting that spot. Honestly, he is wearing the male equivalent to bikini armor, all looks, no practicality.