You make the choice to switch the track to the individual. Although it was an inhumane choice regardless, the needs of the many out way the needs of the...few?
Upon inspection of the *ahem* remains, it would seem that it wasn't a man at all, but a cocooon carrying thousands of spiders. Or previously carrying I suppose, now its nothing but a paste on the ground. Nice infanticide.
You untie the group of four who thank you for your help. They turn out to be survivors from a neighboring village who were under attack by monsters. Those spiders over there would wake up from the sound of the train and eat the remains of the other side. Gross. You feel justified in your actions, regardless of the countless deaths you committed.
Return to the fork?