You are right that "making self-surrender the object of thought, one lays hold of concentration, one lays hold of single-pointedness of mind"- that's a quote from the Pali Canon attributed to Gautama (who was later called the Buddha).
I'm a big fan of Rumi!
As to whether awareness of the small, human, and humble nature of one's circumstance in this life can cause a person to become supernatural, or almost supernatural- I don't know. I've had that awareness a number of times, I think, and for me it passes without resulting in any noticeable change to my monster/non-monster status. Ha ha, if you know what I mean!
Currently I'm convinced that monsters like Chino sensei, Kobun's master, appear supernatural because of their ability to fall upright into trance at every opportunity. My definition of trance is like that attributed to Milton Erickson in the Wikipedia post about him, where his induction of hypnosis in a subject during the course of a handshake is described:
"This induction works because shaking hands is one of the actions learned and operated as a single "chunk" of behavior; tying shoelaces is another classic example. If the behavior is diverted or frozen midway, the person literally has no mental space for this - he is stopped in the middle of unconsciously executing a behavior that hasn't got a "middle". The mind responds by suspending itself in trance until either something happens to give a new direction, or it "snaps out". A skilled hypnotist can often use that momentary confusion and suspension of normal processes to induce trance quickly and easily."
Erickson used self-hypnosis to overcome the pain he had everyday as a result of polio and other illnesses he had experienced; he said this about his use of hypnosis:
"I go into trances so that I will be more sensitive to the intonations and inflections of my patients' speech. And to enable me to hear better, see better."
He saw trance as an everyday occurrence:
"The same situation is in evidence in everyday life, however, whenever attention is fixated with a question or an experience of the amazing, the unusual, or anything that holds a person's interest. At such moments people experience the common everyday trance; they tend to gaze off to the right or left, depending upon which cerebral hemisphere is most dominant (Baleen, 1969) and get that faraway or blank look. Their eyes may actually close, their bodies tend to become immobile (a form of catalepsy), certain reflexes (e.g., swallowing, respiration, etc.) may be suppressed, and they seem momentarily oblivious to their surroundings until they have completed their inner search on the unconscious level for the new idea, response, or frames of reference that will restabilize their general reality orientation. We hypothesize that in everyday life consciousness is in a continual state of flux between the general reality orientation and the momentary microdynamics of trance..."
So I think the reason some masters appear to be monsters is that they are in touch with the dream-aspect of life through the induction of trance in themselves at every opportunity, which results in the sharpening of the senses that Erickson spoke of. In fact, they practice letting go of action and allowing the necessity of their circumstance move their bodies, a necessity which includes all the senses and even what is perceived in the senses but not necessarily manifest in consciousness.
They are faster than the normal person, in a slow sort of way- ha ha!