Back from the theorizing:
I build such an myst. adept for my round and she kicked ass. She dodged everything the four players were throwing at her and was summoning high-level Air spirits at leisure. They did have an explicit anti-mage in their midst, who would Banish her spirits, otherwise, those would have taken the group apart. Also, I opted for no sustained foci, otherwise that would have been a serious liability.
They finally killed her by running her over with a car (at that time, she was out of Initiative, due to some coordinated burst fire, so no Gymnastics, wounded, drained and also down to one Edge. But being run over in a car, after just having summoned a F10-spirit was too epic an end to prolong the fight even further).
The whole fight was 6 turns and got much applause from the players. Never told them, she had no Karma, though Just cheated in some money for a Qi-Focus (for max Reflexes) and a bound spirit to start with.
Broken rules or no, SR5 is a lot of fun to play.
BTW: kill Breakdancer (our group-slang for high-Dodge chars) with lots of bang and/or magic and/or something that you are really good at (e.g. driving cars) and a little patience