Well, shooting all the archers is a no-go. Takes too much power to knock out even a couple, and this fight's just getting started.
<A-Are you sure, Tooru? I couldn't move in that mud! What's the secret?>Do whichever of these two is easier:
Grab the ruined gun and repair it, or
make a copy with totem manip. OMIT THE SCOPE this time! I can't have tunnel vision with all these arrows around.
As soon as Sasha starts to do either,
keep moving through the stands, and make a beeline straight for Alida who's hiding in the entrance. She just wants to be closer to her teammates so she can better assist and vice versa. Dodge, duck and weave around the arrows as necessary. If Sasha gets hit,
Regenerate; if pinned,
Teleport her body out from around the arrow(s), then heal.
Wait until Alida's bodies are at least in melee range of the witch, or the witch actually takes an action. Going to assume as soon as Alida advances that the archers'll begin taking shots, but that'll take a little heat off Sasha, at least enough to line up a shot. It'll have to be a quick one due to how fast and dangerous these arrows are, but that's okay.
Mobility 3: jump on thin air
Sasha takes a
running leap, then propels herself
straight up and forward using a combination of magic-enhanced movement and Teleport. If at all possible, try to momentarily slow my descent so I can aim easier
(double-jumping or w/e should do that, or Aim Glide like in Warframe). This should confuse the archers' aim greatly, enough to do this: Fire a single
Manabolt directly at the Witch, and I want this
firmly at "rocket launcher" power. Try to place it at her legs, such that if it doesn't blast them apart, it will most certainly hit the golden platform she's on and possibly do something to that.
After that shot, get down to the ground safely, using another Teleport to zig-zag while descending if the downward distance is enough that an archer might lead target and hit her. Keep moving, see if Sasha can reach Alida at the entrance or at least get close. Some cover from these shots would be very nice.