Rage vortex of berserking question about exert and multi strike

Hi every one.

I have a question about rage vortex of berserking mechanic.

I know the exerted atk (intimidating cry for example) will stay for the entire vortex duration.

My question is how multi strike interact with this skill ?

Does the vortex will take the more DMG from the final repeat ? Does it only take the more atk speed ?

Is it still possible to exert the atk with multistrike ?

Thank a lot