I came across young man with his legs and arms covered in blood on the way home - way out down some deserted lanes in the near dark. I stopped and he explained, loudly, that he was a self-harmer. He also showed me the empty packet of paracetemols that he'd just eaten. I'd actually seen a slow ambulance a few minutes previously - I phoned 999 and they said they were already looking for him (he'd called in himself but didn't know where he was.) I was able to give proper directions, we walked towards town a bit (me keeping my bike between us) and a police car and ambulance soon found us.
The police officers knew him by his first name and were extremely careful about searching him until they found his razor blade. The guy was shouting that he wanted to be sectioned.
I got a thank-you-thumbs-up from an officer, so I left them to it and rode homewards, counting my blessings.
Sad.