Still working on that Knockback Stuff

Ok i've got a working version supporting all the things i want it to have in:

- Knocks back a Unit
- Unit can crash through trees which deal extra damage
- If the Unit slides close to another Unit, that one is knocked back, too
- This other Unit also knocks back other Units if it comes close

You can try the "Bowling Pin Effect" (suggestion by Litany/Cassiel) out on the attached map, just to the north there's an ogre, bash him and see the effect on the Gnoll crowd behind him. I must admit this trigger gets laggy then (no wonder if you look at the amount of game cache and locals needed) but it's working. And i don't expect people to use this spell against such crowds anyway. However, i didn't manage to keep globals away.
In the end, i had to use one for the more complex functions which create the Bowling Pin Effect.
That's why i'm posting here. Please have a look at the trigger, make suggestions, and so on. Any ideas how to avoid this global ? It's only used in 2 lines, set up and usage, but after hours of thinking i haven't found a way to write around it. Maybe an altered Handle Variables System could work. Why does it need handle subjects ? I tried and altered the Handle Variables to take strings instead, but it didn't work ingame for some reason.