Ok you cant add or take out a thing. No what if's allowed. Its an a or b decision with no alternatives.

You are walking down the street in a foreign country and two government documentation approach and ask in a (you cant refuse kind of way) to accompany them to the enclosed and walled government building court yard.

When you walk through the gate its closes behind you and there are 100 people standing in a line up with a man with a gun at each end.

Two other men approach holding a pistol. They instruct you that you have a choice to make for them.
If you kill 1 of those 100, they will let 99 go free but if you the tourist do not kill 1 they will kill all 100.
You cant refuse to take part.