Here is a UK news report of a man located by a police force drone, and subsequently saved.

It seems that the victims car crashed, and that he then wandered off and fell into a ditch. Not rational behaviour, but perhaps he was dazed or confused by a bang on the head ?

Temperatures were very low by UK standards and is likely that the victim would have soon perished from hypothermia without the search by the drone.

BBC news, police drone rescue