Big Ooze threatens all. Warlock is unconscious. Warblade is standing tall. Warblade took his turn already. Paladin heals Warlock.
Can Warblade take a free/immediate action to “lower defenses” to just provoke an AoO from Big Ooze, in hopes having ooze attack Warblade so the Warlock can stand up from prone without fear of being attacked by Big Ooze?
No, there is nothing the warblade can do in this instance.
First of all, it is not the warblade’s turn. That means even if there is a free-action way to provoke, the warblade couldn’t do it because free actions (generally, with the major exception of talking) have to happen on your turn. He has to use something that can be used out of turn.
That means, effectively, that the warblade has to either make an attack of opportunity, or use an immediate action. Since it’s not the ooze’s turn, it’s not doing anything that will provoke, so an attack of opportunity isn’t available. And since there are no “default” immediate actions, the warblade is limited only to those immediate action he has due to race, class, feats, items, and so on—in a warblade’s case, that probably means some counter. I don’t think any of the counters available to a warblade are things that normally provoke attacks of opportunity.
On the other hand, the paladin healed the warlock. If that was with lay on hands, that doesn’t help (it’s supernatural and supernatural abilities don’t provoke), but if it was from a spell or wand, that would provoke. If the “ooze theatens all,” then it could have (presumably would have) taken that. But it didn’t, so either the paladin didn’t provoke, or the (mindless?) ooze is smarter than you’re giving it credit for. Or the paladin isn’t actually threatened—in which case, if the warblade threatens the paladin, then the warblade could have taken the attack of opportunity—and then maybe done something that would provoke the ooze. But again, there aren’t usually any ways to provoke the ooze while making an attack of opportunity against the paladin.
Which brings us to the question of whether or not you can choose to provoke. We have that question for Pathfinder, and my answer for 3.5e is the same—the rules don’t explicitly allow you to, but considering what an attack of opportunity is, it makes sense that you could choose to have an action provoke when it otherwise would not.
However, as noted in the comments to that answer, I still wouldn’t allow it as a free action, particularly out of turn. Choosing to have some (non-free) action you were doing provoke when it wouldn’t ordinarily, sure, but not just provoke whenever you feel like it.
So at best, the warblade might be able to initiate some counter, or maybe (if the description of the situation isn’t quite accurate and the paladin’s healing provoked and the warblade threatened the paladin—a lot of ifs) make an attack of opportunity against the paladin, and then do so in a way that provokes the ooze. But it sounds like those aren’t options, so I return to “No, there is nothing the warblade can do in this instance.”
