@Dopey
1. There isn't a way to 'fight' for your life, more so that there is a timer. For example, if someone were to stab you, you fall to the ground unconscious and the paramedics have to revive you in a certain time frame. If they don't, you die.
2. When you die, you lose all money and weapons or items on your person. The only thing you don't lose when you die is your clothing, as it makes up your 'identity'. When you die you also respawn at your last save. Generally that would be your home.
3. When someone is charged with murder, it is a life sentence in jail. This is only 45 minutes in prison. I personally believe it should be longer than that, but there you go.
Also, the Devs hope to have as few murders in the game, and more roleplaying. Then will be enforcing this by making it difficult and complex to get your own weapon. You need to invest time in the game if you wish to use firearms. Also, the prospect of prison is what the Devs hope puts people off murder. I hope this helps!