No, I would not press it. And no, I'm not lying (not even to myself). I would never be able to reconcile the fact that I was responsible for someone's death. A person, whose hopes, dreams, and experiences are all snuffed out with a single press of a button. And for what? Money? Money can be made more legitimately, or replaced if it is lost. The same cannot be said of a person's life. Once that person is dead, that's it, they're gone forever. Money, however, is fluid, and it would be a serious irony if immediately after the button press, inflation rendered the currency of choice worthless.
It doesn't matter who the person is. The fact of the matter would be that I killed someone for money, painlessness doesn't matter, nor does the amount of money. Money only has worth because we say it has worth. While it could be argued that human life only has worth because we say so as well, very few people would make such an argument seriously.
I find this lack of empathy disturbing. *breathes ominously through a mask*