Just suppose this large impact simulation actually happened (LGT a video simulation of a 500km asteroid striking the earth. In a nutshell, we all die, pretty horribly, though to be fair it looks like a pretty fast death when it comes). I am assuming that the shock wave would travel fairly quickly around the globe, but that “fairly quickly” in global terms is not instantaneous, I’m thinking long enough for someone on the other side of the planet to know what’s coming (15 minutes? 30? 45? Maybe as long as a couple of hours? I do not know how long it would take, can anyone help me out?) and to realize that there is absolutely nothing that can be done (unless they have a rocket ready to launch that they can stick their baby in, sending him to, oh, I dunno, Krypton), death is inevitable.
Now suppose this person on the other side of the planet is you. You’re gathered with your family, knowing that before too long, all of you will be killed by the shock wave/firestorm approaching. You have a gun/syringe full of a fatal dose of some sedative/a nuclear weapon/whatever- a way to end your family’s lives and your life quickly and painlessly. Do you use it, or do you just hug them tight and let nature take it’s course?