NaBloPoMo writing prompt: If you were walking over a bridge and came upon someone who looked like they were about to jump, what would you do?
I'm not sure what someone could be doing that would lead me to think they were going to jump. It's very likely I would (consciously or unconsciously) convince myself that was not what they were doing.
If, however, I did believe that that's what they wanted to do, and that they were distressed about it, I would talk to them. I wouldn't call anyone unless the person seemed psychotic, and I mean that in the literal sense (If they were hallucinating etc.) For pretty much anyone else, in pretty much any other condition, I would talk, sit, and listen.