In Mandukya Upanishad, the phrase "on account of the shortness of time" refers to the arguments made by the ancient Indian equivalent of the contemporary "Personalist" school of philosophy. The sentence ending "within the contracted space of the body" should be understood also as a temporary lapse from its own standpoint for the sake of overcoming an opponent by using his own beliefs, which, incidentally, is an old habit of the ancient Indian writers. The comment that one cannot confine an idea within the spatial limits of another idea is quite correct. It is amusing to note that Mandukya disposes of the theosophical "astral travelling" as usually understood, but does not prevent the ideas of other persons and places appearing to one's mind--but both time and space are themselves mental. "Travelling" is therefore illusory but the "appearances" may actually occur.
-- Notebooks Category 15: The Orient > Chapter 2: India > # 396