Reference for Eruvin 125:11

ואי בעית אימא שאני רב אחא בר יעקב דמופלג

dignity. And if you prefer I might reply: R'Aha B'Jacob was different from other local authorities since he was a man of great distinction. Raba ruled: When it is a question of preventing one from committing a transgression it is quite proper [for a disciple to give a legal decision] even in his Master's presence.

Jastrow