Armor of Spell Storing & Spell: Frigid Touch

[Matt2VK]

Armor of Spell Storing has the Spell: Frigid Touch stored in it. How do you work the Staggard Condition?

Spell Storing -
This armor allows a spellcaster to store a single touch spell of up to 3rd level in it. Anytime a creature hits the wearer with a melee attack or melee touch attack, the armor can cast the spell on that creature as a swift immediate action if the wearer desires.

Spell: Frigid Touch
Your melee touch attack deals 4d6 points of cold damage and causes the target to be staggered for 1 round. If the attack is a critical hit, the target is staggered for 1 minute instead.

Example -
You are fighting a Gibbering Mouther. This attack stat is what I'm interested in - Melee: 6 bites +7 (1d4 plus grab)

The First melee bite attack hits you. You trigger the Stored Spell: Frigid Touch, damaging the Gibbering Mouther for 4D6 cold damage and staggering it.

Now that the Gibbering Mouther is staggered, it is only limited to 1 action. Now the successful bite attack allows it to try to make a grab attack but after that grab attack, what happens?

[chaoseffect]

Staggered is one move OR one standard but has no restriction on free, swift, immediate actions. "Grab" is a free action so it can make it.

[Matt2VK]

I'm wondering what happens after the "Grab".

[Nicos]

After he have used all his action avaliable his turn is over.

[Just a Guess]

The monster has grappled you (or not depending on the roll) and its turn is over. Directly before its next turn starts the 1 round duration of the staggered condition ends and it can act normally.

So the only thing this spell can do is prevent it from full attacking you on the first turn.