Actually, allow me to disagree.
I think the issue is far less certain.
Hold person is NOT a physical thing but is simply a mental command, a compulsion, which like all or most compulsions gives the victim no choice.
However, what happens when he has two competing contradictory compulsions at the same time is NOT that clear.
What would happen if someone under GREATER COMMAND (5th level compulsion spell) to FLEE is hit with a Hold person? Does the compulsion spell to "stand still" win and the character stops?
A look at the common compulsions spells shows us Command, Hold Person, Suggestion, Greater Command. These are not charms. they do not just change the attitude. They COMPEL you to do as the spell provides.
Similar effects, also mind affecting, and just as "no choice" are spells like scare or fear, although these are NECROMANTIC.
So the just off the cuff hold person wins is odd to me. On what is it based? Why is the ingrained order to stand still automatically given precedence over the same level or higher compulsion to run or to attack?
From what i can see there are several possibilitities when a second and contradictory compulsion is used. All of these assume saves were failed so we do indeed have two contradictory compulsions.
1. First wins. Second spell runs but does nothing unless the first spell's duration until the first spell's duration ends.
2. Same as 1 except last wins.
3. The second compulsion is enough to force a resave, kind of like making you walk over a cliff does, and if the first spell's save fails, the first spell is the winner.
4. The higher spell level compulsion wins. in case of a tie, both are negated until one's duration ends. (Kind of like the way two light and darkness spells work.)
5. No rule precedent at all but you could make the caster level compete by making the second spell have to make a dispel magic-like caster level check vs first compulsion's caster level +11.
Any of these make sense. All of them make tactics.
So what happens when a guy under suggestion to "run away" gets hit with a compulsion to HOLD PERSON? Clearly he cannot do both, which wins? Now reverse the order?
What if the suggestion compulsion cast before the fight was "follow the orders of the party leader" or "do not stand still until all enemies are dead" and a hold person is thrown?
I posted an email to wizards and will post the answer here when i get it. In my games, until then, i will use the spell level option, like darkness and light.
If anyone has a rule which says which compulsion wins or that hold person automatically counters all other compulsions spells, please post the reference.
3. The second compulsions