The one where Carrie gets Aiden to swear on Dior to keep a secret, then reveals that his mate Steve is the unwitting father of the fetus Miranda plans to abort.
This is a scenario that illustrates the difficulties faced by interpreters in some situations where we argue that we have the professional discipline to do our jobs notwithstanding that we possess information that might otherwise might let the interests of the parties influence our work.
On the one hand we have much more discipline than is often assumed, and in order to produce accurate and faithful sentences we need much more contextual and background information than most people realise. But on the other hand there is probably a limit on the extent to which clients should knowingly place us in those circumstances.
The real difficult is of course committing before you know how sharp the conflict of interests actually is.