person A: I was so embarrassed at work last week.  My boss keeps bringing up a mistake I made months back.
person B: That happens_comma_ you have to acknowledge mistakes to learn from them.
person A: I did though_comma_ I've apologized repeatedly.  we've discussed it multiple times.  It's hard because she brings it up in front of others. 
person B: Oh well that seems improper_comma_ you should bring it up to her supervisor.
person A: She doesn't really have one.  She's the PI and her technical supervisor won't do anything.  