Science can provide us insight into the evolution of our brains abhoring the interfering with a person's life for whatever reason and the long term trauma that would be likely caused by doing so even if it meant we would save more lives.
Consider the problem of a burning building with 50 children inside. The only way to save the children would be to prop the door open with a $50 million dollar painting that is nearby. If you save the picture you could use the money to save thousands of children from malaria and a painful death. If you let the painting burn you save the children in the building but condemn thousands of children to die of malaria, blindness and so on. The science of the brain, how it works, how it helps us make decisions, how it makes moral decisions, how it is affected by decisions and so on, can help us to come up with a better morality.
Another question asked related to the trolley problem is would you want to live in a world where doctors kill healthy people to save the lives of sick ones. Understanding the difference between hypothetical questions and those humans have encountered in the real world and therefore shaped our thinking brains, can help us come up with a morality that takes into account scientific understanding.
I have to admit I am not a better thinker than the current best minds in the field of philosophy, ethics and morality.