"go dive for a pearl"

[imchongjun]

Hello, teachers.
Would you tell me what "Go dive for a pearl" mean? I came across this phrase in the following passage:
(A father finds his son slashing the air with a quirt which the latter has picked up from a shop destroyed by an earthquake. The father was previously threatened by a soldier that if he or any member of his family steals merchandise from the shop, he will shoot him dead)
"Well, you just pick it back again. Do you wanna get me shot or something, you little rummy?"
"Go dive for a pearl," Mortimer invited.
It seems to be a swearing expression, and I guess the child is saying something like "Take my quirt away if you can", but I am not sure.

[Anglika]

It's not swearing, just a boy being rude to his father.

"Go away and do something else"

[imchongjun]

Thank you, Anglika. I got it.