This summary is not the rule. The rule text controls.
If you're on the Bar Association's Board of Governors, you can't represent a lawyer who is facing disciplinary proceedings while you're serving on the board. This rule also applies to your law partners and associates. In other words, your whole firm is off-limits for handling these cases during your time on the board.
The idea behind this rule is to avoid conflicts of interest. Board members help oversee how lawyer discipline works, so it wouldn't be fair or trustworthy for them (or their firms) to also be defending lawyers in those same types of cases. This keeps the disciplinary process honest and free from situations where someone might use their board position to help their own clients or law firm.
So if you're a lawyer looking for representation in a disciplinary matter, you'll need to find an attorney who isn't currently serving on the Board of Governors, and who also isn't a partner or associate of someone who serves on the board.