"Fend off the IAA" is an objective in the story mission Three's Company in Grand Theft Auto V.
Walkthrough[edit]
After Michael breaks in and grabs their target, Mr K, you are prompted to switch to Franklin. You now need to fend off a good number of IAA agents who are trying to stop Michael from this extraction.
There are 3 agents to begin with just in front of Michael. Pick them off quickly. After that you have 2 more who come in from the left then 1 from the right. Kill them all and Michael will get pulling out of the building. Now you will need to move between Michael and Franklin to deal with the remaining agents. Immediately change back over to Michael as more Agents appear. He has the better vantage point now.
3 more agents come into the room. Even AI controlled Franklin will give support with the occasion sniping. You have a good dozen agents you need to deal with here. Trevor refuses to bring you up until all the agents are dealt with. Once that is mentioned, you're just about done. Finish off whoever you can see and you are in the clear.
