fall
隕 centers on falling, especially of heavy or celestial objects like meteorites. It conveys a downward motion that is sudden and final.
隕 combines ⻖ (mound, hill) with 員, which likely contributes the sound. The idea of falling may come from something rolling down a slope or a mound collapsing.
The left side ⻖ looks like a steep hill, and the right side 員 suggests a round object. Picture a round boulder tumbling down the hill: it falls.
For イン, imagine an inn at the bottom of the hill where falling rocks sometimes land: inn -> イン, and the rocks fall from above.