I was bored and decided to whip up a intro to a story. Tell me if you notice any mistakes or any suggestions..

He ran. He ran as fast as possible. The man took a quick right through the complex unknowing what was soon to be pain. He took another right and came to a locked door. It was too late. Everything was under lock down. Everything impassable. He stood there immobile.
Red lights swelling across the halls. Screams leaping from darkness many meters away. Darkness hiding death. He pounded on the door. Harder and harder but no satisfaction. The great metal mass stood there looking into his eyes with a grim smirk. Despair overtaking.
He turned around. Running and backtracking. A left and another left and then a opening. A right. “Am I clear?” he thought easily catching a breath. He crouched there behind the comfort of his lasgun through a slit in the wall.
Footfall approaching and a tall lean silhouette appeared ahead. A shot was fired and a corpse laid. Heavy footfall now approached. Multiple footfalls. “S**t.” was muttered.
Further into the complex he ran. His helmet leapt of his head, but instinct was in him. He continued to run. A door was opened. A blade emerged and pain then surged. Blood slowly pulsing and a figure appeared.
Clad in heavy black metal and a blade in hand along with a pistol in the other. A face of terror and twisted death. It lifted it’s arm and walked the man to the wall and held him there. In a quick movement he was disemboweled and darkness took over.

Light warmed his face and figures were dancing. A face showed itself and horror enveloped. Memory returned as the pain revealed itself. A scream tore into the light and laughter took over. Pain jabbed into his side and power was released and his body jolted.
Attempts to move were beaten by straps of dark energy. A glimpse of what was his hand was caught and all that remained was tissue, bone, and darkness returned.

“Awaken.” The word spiraling in his head and a chill through his body. Eyes were opened and a figure stood. “Stand.” Another chill was sent through him. He felt himself standing without restraint. His eyes remained locked on the figure. Laughter subsided. “Well done Imperial,” the voice stinging his ear.
The figure strolled away leaving a shadow and the process repeating itself with another like himself. He followed the shadow until it fell into darkness and was no longer seen.
He brought his hands into the light and metal gleamed and burnt his eyes. His feet were the same. A flashback shot him and he held his stomach. Nightmares flooded his head and his stomach was covered with steel also. He felt his body only to find more metal and less skin.
The man slowly slid his back down the wall and sat staring around his cell. All of it was a shade of black. He covered his eyes nauseated of black and remained still.