Spasms,  whimpering as the body appears to bounce as it's slammed against the surfaces.  So badly you expect to hear a splat like what's found in cartoons.  You were the one, the only one right there. You weren't even in danger, you weren't the victim there. The distance between you and the suffering was less then ten steps away.

You shut the door and tried to do the same to your senses one by one. Your voice was fully operational but it was decided unanimously with every part of you to shut it down.  Letting it run it's course uninterrupted and tragically. You didn't want to get involved,  you decided trying to help would've hurt yourself. 

When you opened up you caught the last moments. Never quite looking the fading life in the eye. You were frozen to the spot shamd by the haunting empty gauze in it's dead eyes.

The image didn't just grow in your mind, it nested and suffocated your dreams in the process.  A penance that shifted into a life lesson. When you finally grasped it instead of running away from it, it was another scene a horrible event in progress. But this time you made yourself be loud. Balancing the scales, not being a bystander, nit looking the other way. Using the guilt,  using you better self and pushing the selfishness to oblivion.