SC2: Smart-cast Multiple Times on Amove

What i want to do: use ability (as corrosive bile) once per click, without requiring new ability key presses between casts (as c). but it has to replace units current orders or a bonus would be adding cast to front of orders queue so unit will go back to its previous task (eg amove).

Using shift only works when at rest because it adds order to end of queue as it should.

Im using queen transfuse ability. it targets friendly units. if you dont line up ability key correctly you select the target unit as you click it. so i guess healing on the move is out?

Added: i will solve the accidental selecting of target by binding ability cast to a key (z) instead of using mouseclick. That's still two keypresses. (If its same key as ability its really buff!)

Rephrase of question 2019-10-29: I want to use shift with abilities for one mouseclick or keypress per use, but i dont want to stop units first.

Added 2019-11-01: Casting while holding shift will take effect when theres no visible enemies to chase. (stricter than i thought.) my test: wounded queens in sight of 1 enemy. stop queens => T => hold shift => click queen => no heal till no enemy in sight.

Starcraft 2 uses a very linear command system. If you issue commands A -> B -> C (even in queue) you cannot then put a command in the middle and have it resume the previous set of commands. Anything new issued becomes the current set of orders. You cannot insert commands into an existing queue.

For your transfuse scenario, you'd probably be best served by either ctrl selecting the queens (or have them in a separate control group altogether) and issuing commands to them while fighting and then going back to commanding the rest of your army as a whole (either F2 or the control group that has your entire army).