Well, there are some "logical" issues such as line of effect. Seems like everyone is in a tent (or in Malkai's case, under the sand), so you can't really shoot anyone with a zap without hitting their tents and possibly burning something. Otherwise Xavier would have to crawl to everyone and shock or shake them. I'd suggest he just screams. I'm sure everyone will hear that, and it won't involve surprising anyone with a zap.