If Russians were sufficiently empathetic towards the suffering of Ukrainians, if they truly felt the pain of Ukrainians as keenly as if they had experienced it themselves, they wouldn't freaking invade. But since empathy is a weak force and it's human nature to not feel much about the suffering of outsiders, Russians are not dissuaded from their war of conquest.
With regards to the weight of violence: Have you considered that "10 minutes of violent murder" may mean only 10 minutes of acute agony for the deceased but years of suffering for the deceased's surviving loved ones?
The only possible answer to your thought experiment is "I don't need s1artibartfast sitting in judgment about whether my life is appropriately balanced between violence and happiness".
That is falling back to the purity tests and cynicism.
To be clear, I'm not judging your life, but challenging your claim about the forces driving human behavior, and the aggregate vale of the species.
I disagree with the idea that just because empathy doesn't prevent all violence, it is weak, or less meaningful. A bird can fly, but that doesn't mean gravity is weak.
Violence is real, and important to understand, but Empathy and good intentions are real too, and a huge part of human psychology. I would argue they are a greater driver of the two.
Yes, human "good intentions" are very, very real and a great driver of history. It is human nature to believe fervently that your own actions are just and right — to which cynicism, or at least skepticism, is the proper response.
I imagine, for example, that government officials involved in managing California water rights[1], have "good intentions" — just as good as the intentions of those in this thread offering monstrous philosophical propositions about bartering violence that trivialize its enduring damage, or the intentions of those who contemplate becoming "nature's ethical guardians" and reducing "sentient suffering".
To the extent that human social systems have evolved to reduce "sentient suffering", it has been by applying forcible restraints on such individuals, confronting them with how the consequences of their actions affect others, even when the natural human inclination is to downplay and dismiss suffering when it clashes with self-interest or "good intentions".
With regards to the weight of violence: Have you considered that "10 minutes of violent murder" may mean only 10 minutes of acute agony for the deceased but years of suffering for the deceased's surviving loved ones?
The only possible answer to your thought experiment is "I don't need s1artibartfast sitting in judgment about whether my life is appropriately balanced between violence and happiness".