Here's an age old dilemma. Often replicated for sake of conflict and tension in story arc, I've never really seen this idea from this angle, and I thought it would be an interesting ambiguously moral choice. To help put things into perspective, here's a quick story to increase the ambiguity as well as the sympathy for all characters involved:
Your name is Billy.
*- Fox Post! -*
Bull shit, my name is Kyle!
*- Fox Post! -*
You are a young boy and an only child. Your father, named Philip, often works far away from home. Throughout your life, you have rarely seen him each year due to being away for months at a time. He calls and writes when he can which isn't as often as you would like, but you love to hear from him no matter what. Although he is gone for so long, his work makes sure that your family is financially secure, and, when he is home, you always have a good time with him. Still, such a distant relationship with your dad doesn't substitute having a father that there for you at all times.
Your father's old and best friend, Daniel, is a familiar face to you. You can remember him as long as you can remember anything else about your life, making him a close friend of the family. Daniel has often come to your home during your father's long trips help around the house in ways your mother can't as well as teach you some cool things. If you've ever had a problem you had to deal with, you would often go to him when your father was on one of his trips.
One day, your mother gets a call saying that the plane your father was flying in had crashed, and it was certain that he was dead. Grief-stricken, your mother has no way to support you, and the possibility of losing your home is at high risk. Daniel, having always been there to help your father and family, lends his support to your family. It starts with a few charitable portions from his salary, keeping up his presence in helping out around the house as he always has. Eventually, it isn't enough, and he offers his home and hospitality to your family. He is more integrated in your life than ever, often serving as a mentor to you, teaching you the ways of life and ultimately helping you growth to maturity. A couple years go by, and your mother and Daniel seem to have taken to each other. Your mother has finally been able to move on in her life, and they soon marry.
However, (you all saw this coming) Philip is discovered to be alive and well, having lived through the crash and surviving as best he can. Upon his return, he is, naturally, shocked at what happened to his family. Your mother returns to her wrecked state, and Philip and Daniel are at a loss of words for each other. You yourself don't know what to make of the situation. Tensions are strained. Any time you see Philip now, he is drunk and spiteful. Daniel and your mother are almost always in a yelling match. Daniel and Philip have gotten into multiple wrestling matches, resulting in the two walking away angry, but not after cursing each other out a few more times. Philip is jealous. Daniel is paranoid. Nothing will ever be the same.
It all breaks one day. You hear screaming out in the backyard. Then a gunshot. You rush outside to see Daniel and Philip--battered, bloodied, and bruised--clawing at each others throats, ready to kill.
Philip, a father who was never there, mad with jealousy of what he feels he deserves by right, circumstances be damned.
Daniel, a suitor who usurped the role of "father figure" in his best friend's family, mad with paranoia of Philip's return taking away what he feels he earned.
A gun is at your feet as you watch the horrifying spectacle. There is no way of knowing who brought the gun into play, with the intention of death.
You pick up the gun and point it. You have to make a decision. Without your intervention, they will kill each other. Kill one so that the other may live. The choice is yours.