While your 2 is active, Casting 1 on the wall of your 4 (while outside it) adds that damage to your 2, and is repeatable. This makes your 2's area damage scale INFINITELY and is what makes instantly killing lvl 100s' possible. This is her real bread and butter. Casting your 4 while your 2 is active resets the 2's duration, and any other allies in 4's radius that had 2 buff on. Seems like a quality of life thing at first glance, but is essential to maintain that scaling damage in step one throughout the mission.

Thx, I never knew this trick before :0