首楞嚴義疏注經 1.351

1.351

引喻難也。如世間人稱見外者，必待出門方名人見。若人居室，門豈自見？門，眼也。人，心也。汝稱眼見，理恐不然。

This is raising an analogy to press the difficulty. Just as when a person in the world is said to see outside, one must wait until the person goes out the door before it is called a person's seeing. If a person stays in a room, how could the door see by itself? The door is the eye; the person is the mind. Your claim that the eye sees is probably unreasonable.