I think rolling is actually slower because by the time you finish rolling, the window will be over and Gohma will lunge at you while trying to get your slingshot out.
I've killed Gohma in 5.6, and being right where the portal is would preserve that time.
So do you strafe around her, or do you sidehop? I've never actually gotten 5.60 and been right on the warp spot, so I think maybe I'm not doing the "movement" part correctly at the start. I roll, and in mid-roll, L-target Gohma, then I do a variable of things after (side hop, strafe, backflip, etc), but in none of my attempts have I actually been right on the portal. Maybe a vid of seeing that would explain it better.