Since Ez hasn't chimed in yet, gonna add that Surana will draw both weapons and position herself between the rocktopus and Sarith. (Not clear on whether it retreated down or along the wall at the same height, but she'll try regardless.)
It's about 20' or so from your starting position. you move at half speed while climbing...so I'm thinking you'd have to dash to get close. You did see what it did to Surana. You could move just a bit and take a ranged shot.