Muffled footsteps. Double. Muffled footsteps. They got closer. Stopped. One set continued after a moment, then the other. Very close. He pulled the trigger. 

The syringe injected into his forearm a clear liquid, and Kray began to grrow in size, veins becoming visible in his skin, his muscles beccoming massive in size. His baggy shorts-luckily they're baggy or theyd rip in half at his growth- now fitting normally. His lab coat slightly ripping in several places, as it was previously too big for Kray aswell. 

He burst from the chest unvoluntarily, but still letting out monsterish roar. He grabbed the clone and hoisted him by the throat with one hand, and punched him through the doorway wwith the other. Attemptinng to follow after his prey, it became known to him he couldnt fit through the door. Easy solution- he ripped several bricks out of each side of the doorway and stooped to get through. His (clone) target unseen, he began to rage, slamming his iron clad fist into walls and boxes and coffins, bewildered at the position of his foe.