Question

How does syntax emphasize the disturbing effect of the subject in these lines from "The Tell-Tale Heart" by Edgar Allan Poe?
I think it was his eye! Yes, it was this! He had the eye of a vulture—a pale blue eye, with a film over it. Whenever it fell upon me, my blood ran cold; and so by degrees—very gradually—I made up my mind to take the life of the old man, and thus rid myself of the eye forever.

The rambling style emphasizes instability.

The first-person narration creates intimacy.

The past tense emphasizes finality.

The abrupt language emphasizes instability.