That's impossible :) In the first turn, the angels won't reach, and the beholders attack in groups. Besides, they aren't alone; sometimes they come with Minotaurs.... So, if the beholders fail to inflict damage on the Crusaders, and the Minotaurs attack them, then...
P.S. I hate Minotaurs; when you fight against them, they can reflect four attacks in a row, but when they are