Unfortunate as it is when you get chewed out in front of everyone else, it highlights one of the realities of jobs like these. When you're hired as a professional, the expectation is that it is YOUR RESPONSIBILITY to play it as close to perfectly as you can, no matter what it takes to do so, and no matter what's going on. If the audience has payed for a ticket and something is wrong with the band, they will hear it, no matter what the reason is. They don't care that the second player sucks, or that there's a technical issue or if someone's dog died the previous night. All that matters is the music that comes out of the pit.
From a musical director's point of view, issues should be non-existent come performance time, especially if they've hired pros.
If there's an issue for whatever reason, and they have a go at you because of said issue, it's NOT A PERSONAL ATTACK. That's the hardest thing to remember. They're not bringing you down as a human being, they're criticising the sound coming out of the horn. Asking you not to play in the last song is not a punishment, it's an adjustment to achieve a musical objective.