And what's worse... had he gone to Mexico, it would have been a royal pain-in-the-a** to get him extradited. Mexico doesn't have a capital punishment statute, so any extradition would probably include that he not be sentenced to death (though that would actually apply more to a Mexican citizen than a gringo).
Forget about lethal injection... how about we give him a summary execution Russian style -- bullet in the head!

"The court sentences you to death, sentence to be carried out immediately! Bailiff, carry out the sentence... but please do it somewhere else... I don't wanna mess in my courtroom!"