Here is a small spontaneous speculation for the morning coffee. We know words and phrases containing skad cig (ska cig seems archaic) “moment.” Before we come to it, consider English expressions such as “in the twinkling of an eye” or “in the wink of an eye” (consider also German “Augenblick”) and “in a snap of fingers.” In the Tibetan word for “moment,” cig seems more or less clear and it means “a” or “one” but what about skad or ska? Without laying claim to any definitive position, skad here could well mean “sound,” “tone,” or, “voice.” The idea behind seems to be that a “moment” is a very short duration/span of time equal perhaps to that of, for example, “a tweet/chirp” of a bird, or of a “snapping sound” of something. We can imagine the etymology of skad cig something like “a tick (e.g. of a clock)” (i.e. “tick” in the sense of “a regular short, sharp sound, especially that made every second by a clock or watch). At the moment, I cannot think of a better explanation. Any insight out there?