The spell in question:
Note: that is the 2nd/3rd level spell, not the more powerful 7th level spell. We're dealing with the wimpy command spell here.
So here is the issue: the players have control of the undead, it is mindless, so the rules say it will even obey suicidal commands. HOWEVER, it also says this: "Any act by you or your apparent allies that threatens the commanded undead (regardless of its Intelligence) breaks the spell."
So is saying "Bite yourself" an act that threatens the commanded undead, in which case the spell is broken? Or is the rule about it mindlessly doing suicidal actions in effect? Which wins? It seems a bit like a race condition where each rule supercedes the other, repeatedly, forever. But what do you all think?