To be honest, it’s what you’ve trained to do. It’s not like they kidnapped you and are holding a gun to your temple and asking, “May we please pull the trigger?” No, you actually volunteered and were chosen from a vast pool of many volunteers.
And now today is the day. The day you will die. You don't have to, of course. No one will threaten you if you change your mind; there will be a vast disappointment of course, and the negative peer pressure would be diamond hard and applied with the force of much megatonnage... but there is no thought of escape in your mind. Oh no.
No, the interface will open and then, inside a field a thousand times thinner than a human hair, the magic. Instantaneous, one-way teleportation to the surface of Mars. It’s hideously expensive; every second open uses more energy than most European countries burn through in a year. All you have to do is walk through the interface, smile for the equipment present, and die.
The surface of Mars is terribly unfit for any kind of life; a naked human being- YOU- with no survival equipment, not even a thin paper gown to cover yourself with, won’t last long at all.
Computer simulations can only tell you so much, after all. Sometimes the best experiments are the most basic. Your corpse will provide data for decades, if not centuries.
All you have to do is walk forward, through the interface, when the time comes. It will hurt, death; no one would be officially disappointed if you didn’t walk through the interface when it opened.
They want you to die for them.