My signature on another forum reads: There are no such things as wrong notes, there's only the look on your face". I got this from jazz vibist Greggory Hutchinson. And I suspect it is derivative of a story Polly related about Milt Jackson (I think) saying something to the effect that they only hear the good notes.
Most of all, calling attention to a mistake is unprofessional in the upmost. Making the mistake is bad enough, reinforcing the mistake by calling attention to it only further degrades the audiences experience of the performance. Reminding them of the mistake that they may have not even noticed, or at least making the mistake the most memorable part of the performance.
Not how any band should want to be thought of or remembered as.
Even evil eyes are unprofessional. As is everyone suddenly spinning their heads around to look at the offender, even if they are smiling. Subtle eye contact from a couple of people is more that sufficient to say "I heard that, we'll talk about it later".
Then it is up to the professionalism of both folks to discuss it reasonably. "Opps, I'm sorry I blew that intro, I was thinking of the next song and got ahead of myself." Or; "Hey, remember we have the break after the second verse. We'll go over it next rehearsal if you feel you need to."
Something often lost at the mid levels is that you are there for the audience, the ones paying the bills, not yourselves. While a bandleader or front person might feel that mistakes on stage reflect badly on them, they need to realize that any sort of reminder to the audience that the performance was less than stellar only reflects on them worse.
I'd approach it on this level. Not make it an issue between two people. Rather a suggestion to raise the professional appearance of the whole band. Down to the sudden glares. You don't even have to get into the level of someone scolding another in the middle of a set. If folks can agree to stop the sudden looks and smile though it for the audience as if it didn't happen, the intruptions and scoldings go without saying.