I figured the wand won't go against it's master and all, so since the master wanted to AK themselves it would have worked. But then again you have to remember a detail, Crouch Jr. isn't using his wand (he couldn't, Dumbledore would know if Moody had changed wands) and we don't actually know if he was the one who won the wand from Moody, could have been Bellatrix, or if anyone did win the wand or just caught Moody some other way. Aha, so which is it? Hum, was the wand his or not? That will remain one of those unsolved mysteries like: what the hell was Denis Creevey doing in hogsmead when he was just a second year?

Thanks!