Leo's passive skill

Today I got a Leo, but haven't had the opportunity to deal with him very often. His 3rd skill (passive) lacks description, so I have a few questions about it.

Eye of the Storm (Passive)
The attack speed of all enemies and allies
is limited to your attack speed. (...)

What happens if you buff your own team with Speed (e.g. using Bernard) and Leo (on Violent Runes) used up his charges before the rest of my team?

Does everyone fall back to Leo's now lower Speed instantly or on his next turn?

Example:

Also, if Leo dies the skill will no longer affect anyone and all monsters will regain their original Speed (if higher than Leo's). But since it's a passive skill, can you disable it (unlike Theomars' Elemental King, which can be put on cool down) with skills other than Tesarion's passive, which explicitly does that?