Luomu Luo'er is trapped in a plight similar to that of the Deceit Tree Seedling. He let the door handle guard the house. They have no direct Soul Contact, nor any forcible contract, just some indirect Prohibitions.
If he returns unharmed now, no problem, the indirect Prohibitions prevent the door handle from attacking him. With his proficiency in controlling the essence, he can suppress the door handle.
However, if he gets trapped here, and Ange and others take over his essence, they definitely cannot compete with the door handle.
This is just like the emperor leading troops out of the city to return; the people in the city will obediently open the gates. But if the emperor is captured and returns, even if they are ordered to open the city, the command might not be effective.
If the door handle obtains control of his essence, then all the power he accumulated will be handed over to a consciousness forged by itself.
This is not something Luomu Luo'er can accept.
