If you rush her on her healing station she should have noticed you coming and fired a good shotgun shot at you first of all. This immediately kills the shield and possibly does some more damage. At this point the Phantom realises trouble is starting and switches to his weapon, probably taking a second shot at the same time. He probably can’t get the 3rd shot off before he’s dead and if he’s managed to dance then she should have reclaimed the heal station area since your melee weapon is no longer a threat.
If she’s using an SMG it is harder for her, but still doable.
The only way he’s scary to her is if he never actually attempts to melee her at all - or manages to slip behind her unseen. In which case again I ask you, this is no different than a slightly weaker Skyhammer, would you make a rage post about Skyhammer as Aura?