The flea rush was used back in the day at regular Desert triad, but it works pretty much the same here.
Problem with the fleas is that once they have been built, K-bot reclaimed, and you rebuild vehicle at the bottom of the mesa, you'r probably not ahead of the other guy even if the rush is succesful. But Andy is hurt pretty bad by the scoutbots and early on Astro's ahead. Andy comes back and even things out, with his advantage in general expertism.