Hello there; I'm coming a little after the battle but... Yeah. I can see where your problem is.
First thing first : How the heck did they never get catched by the police, IRH, or a wandering spirit who smelled all the good magic ?
Do they have the metamagic to suppress their aura or do they only fighted gangers in their home ?
No brcause, once you hit a corpo with runner capable of doing that... The corpos want thoses runners to either :
- Be dead
- Working for them
- Hunted like dog
- Victim of a vivisection.
Anyway. You had receive many path to try and find a solution to your first problem (the better, imo, is to user corridor and situation here the AoE is not only a bad idea, but a dumb idea, the PA and, for the lolz, security team who run like chicken to trap the path of the runners).
Because, yeah, a F12 Lightning ball is something. But if the camera see that... The rest of the security team won't even make it a fair fight : gaz attack, closing door, grenades, other trap like cutting of power on a elevator and forcing them to use stair, etc.
As long as the security don't have the mean to fight an overwhelming power, they won't fight fair but using everythings to help (the flash grenade help as well. After all, the mage can't use spell if he can't see heh).
Anyway, I'm digressing (get used to it !).
Once you manage to make them think differently you're going to have a new whole set of problem : their 40+ of initiative.
What. The. Actual. Heck.
That's... Well. Imagine, if you will, a mage, that act 4 time in one combat Turn. A Combat Turn is a few minutes (3 ? I forgot). It's like having The Flash fighting in front of you but unless fist you see spell being throw at you.
Terrifying.
Because with that much Initiative, losing their electrical toy is not going to complicate life much. Either they're going to use meanier spell (chaotic wolrd, wouhou ! The Hot Potato spell is funky as well). Or simply geek the opposition one by one. And if they can launch a F14 Lightning Bolt without so much as breacking a sweat... So many lower, but as deadlier, spell is not going to scare them.