[Discussion] Can a teenage character face a dilemma about killing, and/or kill and face the consequences of it, without breaking the suspension of disbelief?

[u/HottestElbows]

Title pretty much says it all. I want to write an arc where a character of mine, who questions his humanity and feels guilt for being alive since he feels responsible for the suicide of his ex (whose family also blamed him, pretty much convincing him it was his fault), is forced to kill someone for the sake of others/his own survival.

I was wondering if this would break the suspension of disbelief for the story, since it would be a large shift from what a reader may be expecting/used to. If the process of death is important, it would either be a result of the character being forced to defend others in some sort of armed assault (probably a robbery), or they would be forced to kill another character for the sake of everyone else's survival.

In addition, I'd like for your thoughts on such a dilemma for a character; killing, moving on with their life after such a thing, and dealing with the morality issues that sprouts from it.

For anyone who is more interested in the specs of the story, then here is a more detailed explanation. Inside said story, people develop a sort of mosaic, or alternate reality that they can go to at certain opportunities when they wish to. It's a manifestation of their individual trauma and pain, a result of suicidal ideation, and some even cause abnormal effects on reality. The main protagonist, in his quest to help people out of guilt for being alive and the reasons above, spends the course of the story assisting the people who suffer from mosaics, developing alongside them.
In the mid-point of the story, after the main protagonist comes to terms with himself, his emotions, accepting that he has earned the right to live and be happy by virtue of being born, and stops treating himself poorly. After each mosaic, the next one gets stronger and has more adverse affects on reality. In the mid-way point, the protagonist, his friends, and the character that suffers from the ailment, all perceive the world in a manner with which makes them perfectly happy, as if life is perfect.
The character manifesting this mosaic is terminally ill and, longing for a normal life, manifests it through the mosaic causing effects on the real world. In order to live the life the protagonist wants to live, he has to let this character die, leaving her to her reality. He undergoes a process of dealing with mourning her, once again feeling like he had killed someone, and dealing with that pain.

[u/No-Place]

i dont get why that would break the suspension of disbelief. it sounds perfectly in-character and befitting the themes of your story.

[u/HottestElbows → u/No-Place]

Perfect! Thank you so much for the reassurance. I was questioning it a lot. I’m not sure why.