the understanding of a sentence

Question

Once scouts reach that decision, their behavior changes. Each scout dashes back to the nest, but instead of coaxing a nest mate for a tour, she just grabs somebody. She uses a mouthpart hook, an over-the-shoulder throw, and off she goes with the passive nest mate curled on her back in an ant version of the fetal position. Carrying takes about a third as long as leading would, and scouts can haul the rest of the colony to a new home within hours. The ants shift from the independent info gathering of scouts to group implementation of the quorum's decision.

I do not understand the usage of in the bold sentence. It throws me off when only "off" stands there. On top of that, though it is logic to look "an over-the-shoulder throw” as an appositive of "mouthpart hook," but I just do not think these two are connected.

Answer 1

I'd parse it like this

She [subj] uses [verb] a mouthpart hook [obj],

{and she uses} an over-the-shoulder throw[obj],

and off [adverb] she [subj] goes [verb]...

There are three coordinate clauses. The structure of the third one is idiomatic. It is close in meaning to "away", with the sense of "away from that place". So "off she goes" means "she departs".

The rest of the sentence is a series of adjucts each of which tells us a little

with the passive nest mate [a preposition phrase, the nest mate is the other ant]

curled on her back [a participle phrase describing the passive nest mate]

in an ant version of the fetal position. [another preposition phrase]