Clark wasn’t sure how exactly to deliver Lois’s note to her sister.
Good, she is warning Lucy. Lucy deserved more mention in the show than she got.
Dropping Jimbo from the skies wasn’t exactly an option either.
Especially since he's the out-of-favor boyfriend.
Too many people in this dimension already knew that Clark Kent had extra abilities; he didn’t need one more.
He already has one more, at least.
The best option seemed to be to slip the note under Lucy’s door, but that wouldn’t guarantee her finding it. Clark hated this idea, mostly because of what he discovered shortly after he arrived to help Jimbo move over to his place.

he found the note.