What the Mindscape can be easily used for is to return to a place where they've been before. In this case, what they did was to return to the location where they first entered the Mindscape.
Then they left the Mindscape. This made them appear at the exact location they were in the Hydra Kingdom when they first entered the Mindscape.
They appeared next to the thief as a large black winged bird with arms attached to their chest. Then they controlled their thief slave to come over.
After the thief slave came over to them, they implanted another mark of bondage into him. This mark of bondage was to gain control of his Thieving Hands divine ability.
After they gained the divine ability, they tried to use it on the virtual flesh. They tried and failed to do so because they couldn't touch the virtual flesh with their hands.
The Thieving Hands divine ability is an ability that thieves possess that they use to steal ownership of any item they can touch.
