For tl;dr you can cast adlo and succor immediately after using emergency tactics while it is still in animation. The ability is fine as is.

In cases that. You needed it when you are out of or holding aetherflow stacks and/or indomitablilty is still on CD,
Succor > emergency tactics > succor

I use it less with adlo unless tanks are dangerously low on HP as it is still more MP efficient to go with adlo then physick and manual embrace spam.