At 31:00 vook plusses lili to discard a chalice. Doesn't it make a lot of sense in that situation to cast the chalice on one? Since that's what ultimately locked up the game in the end? I mean sure it could have gotten hit with k command but then you are still in the same situation as when you discarded it.
I believe his hand was answers to moon, one of which being vindicate, and non-basic lands. He knew that his out was drawing two mox diamonds and needed to maintain 2 lands and 2 answers in hand if he wanted to get out of moon. Chalice isn't what the game was about at that point.