It sure doesn't seem like a game of chance when generic monsters are holding all the cases and he's a captive contestant in a game show. Seems like a means of murder. So Garrot just scoffs, closing the distance between himself and one of the cases.

"I'll take number thirteen." And he reaches out to take it from the holder, if he can. Rather childishly, the 13th letter of the alphabet is M, which reminds him of Murtakorp, his family, and his daughter Miri. What a sentimental goob.