Pitcher game status = break glass guy

Isn't the "break glass guy" who you call in case of emergency because the whole situation is going up in flames, just like you break the glass to reach the fire alarm? I think it's a standard for many sports and jobs where you have to have a backup for emergencies.

My son's coach HS coach used it one time that I know of.  Two main pitchers on the team then a serious drop-down in talent, a couple of kids that can close a game ok, and then a more significant drop.  HS Tournament with 4 games in a 6 day period. Stud #1 pitches all/most of game #1.  Opponent for game #2 is considerably less of a threat than games 1 & 3.  Coach decides to hold son off until game 3 but says "You're my break glass guy".  He went through the bullpen and they did ok, but in the bottom of the 7th coach broke the glass.  Pitcher had managed to load the bases and get only one out, even though we were up 5ish to zero momentum had shifted and it was time.  Pulled son in from the outfield for a quick warmup, run comes in while he's still doing that, bases still loaded.  Son get's two strikeouts on 8 pitches, game over win preserved.  Fire out. (This would be a really impressive story without the context of how weak the othe team was.)

That kinda makes sense (fire extinguisher analagy)...my son is that guy in college rn..freshman. coaches gotta see what he can do. so why not throw him into the fire....haha. should be interesting next couple of games.

This is the guy in the bullpen whom I always called the fireman.  That's his job, to come in and put out the fire.

So what is it about this guy that puts him in that role? Vs another. I mean if he’s that good at putting fires out wouldn’t it be better to not let the fire get started in the first place? Just trying to understand the thought process that creates this role