Forbidden Remorse - Derek Shepherd and Gary Clark

Prologue

"Mr. Clark you don't want to do this," Derek said with his hands up where Gary could see them.
"Well Dr. Shepherd, I do actually want to do this, otherwise I wouldn't be doing it, now would I?" Gary replied with an evil smirk. The gun cocked once and fear shot through Derek's entire body. He was going to die. He would have to leave his beloved wife and the unborn child of which he had no idea about.

He began apologizing mentally to Meredith, his wife, when the double doors banged open and a short brunette raced in. Derek whirled around to meet April, one of his surgical residents. Stupid move. Gary's finger pressed the trigger just as Derek was turning back to face him. The bullet hit him in the chest and he collapsed to the ground and his world went blank.

Gary looked down at the victim and smiled to himself. The brunette was stunned, her mouth agape. The man raised his gun again, this time aiming for the terrified resident. He didn't need to shoot her, like he needed to shoot Shepherd. The brunette wasn't a murderer, Shepherd was. He had killed Gary's wife by unplugged her for supposed brain death.

"M-my name is April Kepner, I-I'm-" the brunette began. Gary silenced her with another cock of his gun.
"Shut up," the man told her. The terrified resident obeyed and quickly shut her mouth. "Go. Go before I shoot you too," Gary said as he looked down at the man laying limp on the ground. The deed was done. The brunette raced out through the doors and Gary turned around, walking through the set directly across from them.

When he shut the door behind him, he heard loud shrieks. He didn't bother with them as he causally slipped his gun into the pocket inside his suit, and strolled out the emergency exit so that SWAT wouldn't catch him.

That was the last anyone had seen of Gary Clark.
Until it wasn't.