Ahri W: "Fantastic Fox-Fire" 5.2 patch

I have a small concern about Ahri's new Fox-Fire (W), 5.2 patch. Here is the blurb on the mechanism change:

FANTASTIC FOX-FIRE : Fox-Fire's targeting system has been improved and will now attempt to acquire a target if a new target if the original target is going to die from other Fox-Fires.

Theoretically, it makes sense to spare the overkill of one target to deal damage to other targets.

But what if the "killing" FF#1 is in transit to its target, but FF#2 and FF#3 attack something else to spare overkill and the target heals sufficiently to survive FF#1? Does each FF wait for the previous one to land before firing?

Very small time frame, and very small issue, but it could mean the difference.