The angrier he gets, the less stable his augments become. This always ends in his evolved form unleashing, known as TOTAL CORE by the people who have seen it and lived.

Faster, more agile, and evisceratingly sharp, he is actually more vulnerable to damage in this form due to his nanites being spread out across his new limbs and enlarged body. That of course doesn't matter once he has you... when he goes total, blood WILL spill.