I Promise Not To Tell

In "The Cloud" from "Star Trek: Voyager," Tuvok chastises Kim for commenting that he's never seen anything like what they're seeing, saying that it could make the junior officers nervous. A bit later, as Voyager encounters an anomaly, Janeway asks for Tuvok's thoughts, but Tuvok admits that he's unable to offer identification. Kim them comms him, saying that in other words, he's never seen anything like it. He promises not to tell the junior officers.

Example of:
I've Never Seen Anything Like This Before