destroyed, ruined, to subvert, to injure
圮 centers on collapse and ruin: something destroyed, broken down, or subverted. The idea of injuring or overthrowing extends naturally from bringing something to ruin.
圮 combines 土 (earth) with 己, which likely contributes the sound. The idea of earth collapsing or being destroyed fits the meaning of ruin.
The left side is earth 土, and the right side is 己, which looks like a twisted, broken structure. Picture the ground giving way and everything built on it crumbling into ruin.
For ヒ, imagine a ruined building with a single surviving beam sticking out, shaped like the hiragana ひ (hi). The ひ beam is all that remains of the destroyed structure.