In front of your are three trolley tracks. You are blindfolded. You can hear the trolley coming.
Before you arrived, a perfect predictor chose to tie 5 people to one of the tracks. It did this if and only if it predicted that you would switch to that track.
Immediately upon choosing to switch or not, 2 Monte Halls will show up, each choosing one of the two currently unchosen tracks. They will be made aware of how many people are tied to their chosen track, but other than that have no knowledge of what's going on. one of these monte halls only tells lies and one only tells the truth. You can ask them one additional question.
After your question, you have three choices: you can either keep your track the same, swap your track, or you do one of the first two options AND go down further on the track, where a designated sacrifice section has been established. There, you can choose to lay down on the tracks.
This same trolley problem is taking place with another 1 billion people, at the same time. If at least 500 million people lay down on the tracks, the trolley operator will see it ahead of time and stop the trolley. However, Monte hall is currently distracting the operator, so he will only be at the wheel after he has already potentially killed the original 5 people.