Han Sen had no interest in humiliating Ji Yang Sheng, and he didn't really want to get in the carriage. He just wanted to see if he could draw out some of the Demons that might be nearby.
If they wanted to save Ji Yang Sheng or eliminate Han Sen, it would be hard for them to do that in the core area. It would likely prompt would-be saviors to use their Demon Dolls.
Han Sen's true purpose was to lure out more of those Demon Dolls so he could take them for himself. It would be great for him to have a few deified Demon Dolls in his back pocket.
The existence of the Demon Dolls was a very strange thing. The Demon Doll Han Sen had already obtained had a lifeforce and could think for itself a little. It never looked like it was truly alive, though.
Its mind only came alive when it received commands via the purple horn. If it wasn't being controlled, it would stand in place like a deactivated robot.