Officer Chris Kirn was working patrol when the call came in: There’s a man on top of the Maple Street Bridge and he’s threatening to jump. It was about 9:15 a.m. on a Thursday in October, cold but sunny. A slight wind. If not for the young man, thought to be in his 20s, clinging to the outside of the bridge’s tunnel-like chain-link fence, it could have been any other autumn day.