This passage describes the way Scylla devours the sailors.
The entire passage is a metaphor. Scylla is being compared to a fisherman. The fisherman is throwing out his bait and whipping up fish out of the water onto the beach where they struggle to breathe. Scylla is doing something similar with the way she plucks the sailors from the ships and devours them. Nowhere in the passage does it talk about Odysseus saving his crew or escaping Polyphemus. Even though it does describe fisherman, the purpose is as a comparison to Scylla's behavior.
