In my experience this can vary so much depending on the character structure and the design of the roleplay. Some are simply immune to such horrors and sadly those ones have to be played out like the hero of an action movie; killing people like pawns on a battlefield. For me, this is less fun as I like to play around with the emotional impact that it can cause and the trauma inside the character's head. [i](Just take a look at my Madison character when I had her wake up after an amputated arm and an eye removal)[/i]

As someone who has suffered from some serious anxiety and depressive stages in my life [i](Don't ask for shits and giggles unless you really wanna know... but they got pretty bad)[/i] I find can utilise these as an understanding for what a character [i]may[/i] feel. It's not going to be along the same vein, but death is disturbing and it affects the people involved in very similar ways. Adding things like relapses, failure to perform simple tasks, loss in concentration on a task at hand and altering the character's emotions all contribute to that helpless feeling that they may be feeling.

It also depends if its accidental or on purpose...
[list][*][b]Accidental:[/b]
Can appear as someone that will instantly tend to the person in the hopes of righting what is wrong and what they essentially fucked up. The character will often feel as if they should be the one to die instead and will possibly wish that they were the one that died instead.
[*][b]On Purpose:[/b]
This will depend on whether it's the first death or not. Hotline Miami actually showed this off in the best way during the first few scenes. The main character, Jacket, just killed a whole bunch of people with no remorse but then kills an innocent homeless guy. Upon walking away he stops and spews on the ground, showing that he feels a deep sickness for what he has done.
As the character moves on they could become more and more violent or start to suffer from symptoms like PTSD, flashbacks and/or nightmares.[/list]

Again, this is all based on a bit of a black and white view, but you can have someone that is a killer on purpose and suddenly relapses into regret. Pretty much if you can fuck around with the character's mental side and break them down into nothingness, then you might be doing something right.

[hider=Not really a murder scene, but a scene that displays the horrors that someone may face]
[color=a187be][b]"No... No. No, No, No!!"[/b][/color]

Heart monitors started screaming as her adrenalin began to kick in. Even in her weakened state she shot up in her bed, pulling on all the cords attached to her body and hearing the crash of medical equipment on the ground, but her hand was still ripping into the layers of bandages around her hidden arm until she had exposed what she had feared the most, a limb that wasn't of her own skin and bone. She thought she was only having a nightmare where she continually recalled the misguided words from the medical staff. She didn't expect them to be true. After just waking up and exposing her arm she simply sat there in shock with her mouth open in a silent, harrowing scream while the tears began to form on the corners of her eyes.
[/hider]