Derek was still alive.
He was living a life worse than death at that time, but he survived and watched these scenes one by one.
Watched how the person who saved him was coerced and there was nothing he could do.
Watched how the person whom he cared for had to die because she couldn't bear to live anymore.
Watched as the person who was praised by others and had such high power was such a scum who should have died.
So what if he had a lot of power?
Someone who kept on backstabbing others in order to gain power deserved to die.
It took a long time when more and more extremely large mutated animal and even more powerful extremely large mutated animal appeared that Sean and his entourage finally died.
Derek waited until that day.
Then he killed himself.