Ι finally figured it out! I had already created a separate input action called “Fly” back when I hadn’t figured out how to set this all up on a single input action (jump). It is practically the same as the “jump” action (digital (bool) type with Space Bar set up as the key value in the IMC. So I just used that one to clear the timer and call the “Falls Down” function 
So in case someone else has the same issue, here is my completed blueprint (so far):
And, again, this is the Falls Down function.
I’m marking this as the solution, but I wouldn’t have done it without your help, @SolidSk, so thanks a bunch!