This was heard in an administrative hearing. It is a conflation of “walking on eggshells” (to act with great care so as not to upset someone) and I think “live in a glass house” (be susceptible to judgment or criticism). Eggshells and glass are both very fragile, and I think the speaker was thinking of both. “Living on the edge” (doing something daring or bold) might also be in the mix, with an eggshell (Humpty-Dumpty?) sitting on the edge of a wall. Any other thoughts? A big thanks to Sam Edelmann who heard this one and passed it on.