This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The historical origin of 镾 is uncertain. It visually combines 镸 (long) and 爾, but the exact development is unclear.
Since the meaning is uncertain, focus on the shape: a long 镸 side next to the complex 爾. Imagine a long, tangled thread that needs mending—tying into the vague idea of repairing or crossing over.
For ビ, imagine a bee (ビー) buzzing around the long, tangled shape of 镾, trying to mend it. The bee's buzz cues ビ.