What is "gone deep"

Usage examples of "gone deep".

The scars were along the wrist, not across it, and must have gone deep.

It was bleeding pretty freely, but he didn't think it had gone deep enough to hit an artery.

The sting of the slight had gone deep, but the apology was so prompt, and so evidently sincere, that the hurt was almost immediately healed, and a forgiving smile testified to the kindly Judge that all was well again.

Sure, we're trained and equipped to deal with a whole range of combat psychoses, but wherever this guy has retreated to, he's gone deep.

His glove came away wet: the blaster burn had gone deep through skin, nerves, and fat, cauterizing blood vessels but exposing raw tissue that wept plasma.