Exile, imprisonment, forced servitude as a monk while getting to know God... Doesn't matter. Imagine whatever. The only bottom line is that murder is wrong, for several reasons - its so wrong that its wrong from multiple viewpoints. Don't do it. The state is definitely committing murder when it executes someone because that person is already in custody. Not a threat. They are under control. So a jury deciding to kill them is no different than you colluding with your buddy to kidnap someone and then murder them. Its the exact same scenario. You and your bud may think you're entirely justified. Its the same.