>If you can choose which specific human dies (but it can't be someone who wishes to die), does that change your answer?

I think for anyone who would, with the original question, choose to let the pandas die should change for that version. I can think of plenty of people whose death would be a good thing for the world. Putin, for example. If I had a button that would magically kill him, and not do anything else (like saving pandas or whatever), I would push the button. He is presently getting a lot of people killed, and it would be far better if someone had killed him before he started the war against Ukraine. Still, better late than never. It likely would help end the war if he were to die now, and save many lives.