Will somebody arrive mid-fight to seize The Gate?
Short answer: no, unless you refer to the IFCC showing up once The Order and Team Evil commence combat.
Here is my estimate on how IFCC does that: the three fiends have a link to V provided by the soul splice event and their ability to call V back two more times.
That link permits them to intercede on the mortal plane wherever V is.
I have no idea if D&D 3.5 has a mechanic like this, but it seems a heck of a lot less complicated, as magic goes, than the soul splice was.