Does gaining immunity to a condition apply immediately to a current condition?

Question

What happens when a creature gains immunity to a condition while it currently has that condition? (For a list of conditions see Rules Compendium 229–35.)

For example, the level 6 battlemind daily utility power mental triumph (Psionic Power 39), in part, says, "You cannot be slowed, immobilized, or restrained until the end of the encounter." If Sivart the battlemind presently possesses the condition immobilized and takes a minor action to use the power mental triumph, does he lose the condition immobilized? Or, after he uses the power, must the duration of the condition still expire normally and thereafter—for the encounter's duration—he can't be immobilized?

By way of metaphor, can an inoculation also cure the disease?

Answer 1

Immunity to a condition means ignoring that condition.

A creature that is immune to a condition or other effect (such as the dazed condition or forced movement) is unaffected by the stated effect.

• 4e Rules Compendium, p.225

It's best to think of this as the effect still existing on you but being ignored - you can still have effects that slow, immobilize, or restrain applied to you after you use mental triumph, but you ignore that specific condition. For example, if you're hit by a toxic web that slows you and does 5 ongoing poison damage, save ends both, you are not slowed but still take the ongoing damage.

This is important for handling non-permanent immunities in general. Suppose, not by way of metaphor, that you're being affected by a disease that has progressed to the point that it slows, immobilizes, or restrains you. Using mental triumph will allow you to ignore that effect of the disease until the end of the encounter, but it won't actually cure the disease and you'll continue to suffer from its effects when the encounter is over.