Something that has lately amused and puzzled me

Why is it that, after The Man is received into a cloud, "behold two men stood by them in white garments"? Continuing,
"¹¹ Who also said: Ye men of Galilee, why stand you looking up to heaven? This Jesus who is taken up from you into heaven, shall so come, as you have seen him going into heaven." Not that it is unusual for "men" to appear and disappear, in the Inspired Record of Salvation History (it might have been unusual in an absolute sense, but the Bible isn't about business-as-usual), and yet... Is it, for instance, possible that the eleven were in danger of lingering by the mount untill they sequentially keeled over for hunger and exhaustion? Why, for this very practical nudge, is it so conveniens that it be delivered by angels and not Our Lord who, really, was just right there. And what about their non-question interjection: "[he] shall so come, as you have seen him going"; is this advice to them, and how is it not the answer to their own question, "why stand you looking up to heaven"? I presume they were angels, for Peter and James and John would recognize Moses and Elijah, and Luke would have said so if it were them again.

These are some things that lately have puzzled and amused me.

Any thoughts? (please limit your comments to less than 1 megabyte in size)