Q: What does this couplet mean when there is an empty door in the room?

This couplet seems to have Zen meaning. People in the house are trapped, that is to say, people are trapped by themselves, by their own hearts, by their own obsession, and it is difficult to disappear. Therefore, they cannot get rid of the entanglement of the world of mortals. In the sense of this word, it means that there is a door at home, but this person is unwilling or unable to go out. In fact, this person clearly knows how to "go out" but has no intention. He would rather repair himself than hurt himself. Meaning? All the people in the world are trapped in this quagmire, but they are helpless. The so-called involuntary fear is that there is no empty door, which is what Buddhists call "empty door." They said that this person is willing to enter an empty net, so he can't see through the world of mortals, can't get rid of his inner stubbornness, and can't liberate himself. He's just trapped on himself. "Empty door" can also be understood as "enlightenment", and the combination of enlightenment is to comfort the world.