The Carnival game Bluff is confusing me. I thought I was finally getting it, and got the opponent down to 3 dice while I still had 5.

So, my opponent has 3 dice - 1, 2 and 5 They bid at least four 5s.
I challenge it (because they only have 3 dice)

I lose the challenge and a dice. So, how does that work because I'm very confused. I know 1 is a wild card, but not that wild, surely? Anyone know?

Edit - okay, I see now. Can this be locked please?