Even in our more enlightened times, a SWAT commander wouldn’t want to be known as someone with depression or other mental illness issues. Back then, even less so - so JD was dealing with it as best he could without ratting him out to management (and I don’t recall him as being presented as any kind of deep thinker/planner).
Good points, but there has to be some balance between covering your buddy’s ass and knowing he could be suicidal. The way it went, Howard would indeed have been dead that evening IRL.
As I recall, the guy was a mayoral candidate who was leading a group of reporters through a housing project, talking about how shoddy the construction and maintenance was, and how he’d do better if elected. “And look at this this so-called ‘safety window’…” he said (more or less) as he leaned against a window to demonstrate its flawed installation, and it unexpectedly collapsed at his touch, sending him and it to the ground.
On researching it, the character’s name was Ben Fisk, played by George Coe.
Spot on. I remember now. Thanks. 
The forgotten SNL cast member
Some additional info:
[ol]
[li]In addition to being shot during a drug-bust-gone-bad-that-was-actually-a-setup and getting accidentally shot with his own gun by his girlfriend’s little boy, Washington also got winged during a bust of some dirty cops in a tailor shop. This was kinda fortuitous, as it got him a legitimate prescription for codeine, which he had been taking on the side for his bad knee.[/li][li]Mick Belker got shot during an undercover. I forget the exact circumstances, but this was when he was married to Robin Tataglia, so it was fairly late in the series.[/li][li]Coffey was also shot (in the shoulder) during the cop-killer arc in season 4. He and Bates were manning a “mini-precinct” storefront operation at this time.[/li][li]Henry Goldblum got shot while doing an undercover, pretending to be a john who was being busted by fake cops in order to extort money. The “hooker” unfortunately happened to be packing as well.[/li][/ol]
JD LaRue was a very (you’ll pardon the expression) shoot-from-the-hip kind of person. Lived by his instincts, which made him an above-average cop and often a below-average human being. If he had taken ten seconds to think about what he was doing, he probably would have talked himself out of replacing the live ammo in Howard’s gun.