After a few runs, and trying what ppl said here, what worked for me as a guardian was:
- with staff equiped, use RETREAT rigth after the cinematic, use staff 3 ( symbol of swiftness) wile in more or less close to her ( mid way) and runing a litle to the rigth side, dodge the circles in ground just by runing and press F, may take some pratice, dont need to dodge after starting the F, just need to get that faster, thats why i used RETREAT + STAFF 3
SRY if some words are wrong, english is not my native language
have fun