Disable knights vow passive once you are at a low health percentage

The other day i was playing taric and teleporting back to base with like 3% health. My adc passes by and takes an ezreal q and a morgana q which killed me. I feel like it should work similar to bond of stone, where it deactivates at a set percentage of health.(probably 5%) And while you're at it make an indicator on how much dmg was absorbed/healed, i'd be curious to see that.

What do you think about that?