Verb + 就 + Verb (indifference / a shrug)

"Fine — … then, so what"

• Verb + then / just就jiù + (same) Verb = a shrug: "fine, (let it) … then / so what if …".
• to go去qùthen / just就jiùto go去qù，to be afraid怕pàwhat什么shén me = "fine, I'll go — what's there to fear?"
• bad坏huài(completed / change)了lethen / just就jiùbad坏huài(completed / change)了le = "so it broke — never mind."

Verb + then / just就jiù + Verb

• Repeat the verb around then / just就jiù to wave away the consequences.

go去qùthen就jiùgo去qù，fear怕pàwhat什么shén me。

• to go去qùthen / just就jiùto go去qù，to be afraid怕pàwhat什么shén me = "fine, I'll go — what's there to fear?"

Recap

Read the full reference: HSK 5 grammar — Sentence patterns.