You arrive as an honoured guest into a country. You are tasked by your own government to report back on the realities on the ground.
There is a popular uprising in the country you have been sent too. The regime in charge is using the security forces to put down an armed rebellion. You are taken to a village at the centre of the uprising. There you witness the security forces rounding up 30 civilians of various ages. Upon discovering your presence the officer in charge informs you that you are the first foreigner ever to visit that village. He considers your arrival a special occasion. He informs you that the 30 civilians are to be put to death as punishment for armed attacks on his security forces carried out by the civilians family members.
He then says "To mark this special occasion as is custom of our country, if you will choose just one of the 30 and kill that person yourself. I will allow the other 29 their freedom. If you decide to turn down this honour I have no choice but to execute all 30."
He holds out his hand. You see he is handing you his revolver.
One of the civilians walks forward. He is old he begs you to allow him the honour of dying to save the others.
There is no reasoning with the officer. It's you killing one or him killing them all.
What do you do?
shoot the officer. You do have his pistol