You pretty much summed it up correctly.
The incident you remember is from Assassin of Gor, pages 251 through 312.
Here now are the pertinent sections
"Do not look further!" she cried.
"Be silent, slave," said I, poking about, and then I saw in the bottom of the chest, almost colorless, ragged, not more than a foot high nor a few ounces heavy, a small worn, tattered doll, dressed in faded Robes of Concealment, of a sort little girls might play with on the bridges or in the corridors of cylinders, dressing it or singing to it.
"What is this?" I asked in amusement, lifting it up and turning to face Sura.
With a cry of rage the Pleasure Slave ran past me and tore the slave goad from the wall, flicked it to on. I saw the dial rotate to the end of the red band, to the Kill Point. The tip of the goad, almost instantly, seemed incandescent. I could not even look directly upon it.
"Die!" she screamed, hurling herself toward me, striking with the goad.
I dropped the doll, spun and managed to catch her wrist as she struck downward with the burning goad. She screamed out in frustration, weeping. My hand closed on her wrist and she cried out in pain, the goad falling to the floor, rolling. I hurled her some feet across the room and retrieved the goad; it had stopped rolling and now, burning, had begun to sink through the stone. I rotated the dial back to its minimal charge and then flicked it off.
I let the goad, on its leather strap, dangle from my left wrist and then I went to the doll and picked it up. I approached Sura, who backed against the wall, closing her eyes, turning her head to one side.
"Here," I said. I handed her the doll.
She reached out and took it.
"I am sorry," I said.
She stood there, looking at me, holding the doll.
Assassin of Gor    Book 5    Page 251
"How is it," I asked, "that you have such a doll?"
She said nothing, but returned the doll to its hiding place, beneath some silks and jewelry, at the back of the chest, in the right corner.
"Do not answer if you do not wish," I said.
She returned to where I sat and knelt there across from me. She lifted her bowl again to her lips and drank. Then she looked at me. "It was given to me," she said, "by my, mother."
"I did not know Pleasure Slaves had mothers," I said. I was sorry I had said this, immediately, for she did not smile.
"She was sold when I was five," she said. "It is all that I have left from her."
Assassin of Gor    Book 5    Page 252
Now, unhooded, but chained, I knelt bloody before the dais of Cernus.
A few feet from me, wretched, dazed, chained like I before the dais of our master, knelt Elizabeth Cardwell, her only garment the chain of Cernus, with its medallion of the tarn and slave chains, about her throat.
To one side, to my dismay, I saw Relius and Ho-Sorl chained. Near them, kneeling, her wrists and ankles bound with slender, silken ropes, knelt Sura, head forward, her hair touching the floor.
The doll which she had so loved, which she had had from her mother, which she had so jealously protected in her compartment that she had attacked me with the slave goad at the kill point, lay on the tiles before her, torn asunder, destroyed.
"What is their crime?" I had asked Cernus.
"They would have freed you," laughed Cernus. "The men we apprehended after severe fighting, trying to cut their way to you when you lay in the dungeon. The woman tried, with paga and jewels, to bribe your guards."
Assassin of Gor    Book 5    Pages 311 - 312
