Way to unlock: You need to complete main mission 65 (Architect's Plans) and select the variant that assumes disguising as firemen (Fire Crew), towards the end of that mission. There is no marker for this mission and you can start it anywhere.
Playable characters: Michael
Additional information: you have already had the opportunity to play a similar mission earlier throughout the campaign .
This time around, for your getaway, you need to pick a car capable of taking four people, at least, but this does not matter if it is going to be some slow pick-up truck or a fast car. Just like before, you should spend some time determining the spot to park the stolen car. The main part of the heist is, of course, going to take place inside the FIC building, i.e. in the center district of Pillbox Hill. This means that it would be a good idea to hide the car somewhere nearby. Pick a side-alley, at a discernible distance from the main road (the game will let you know if it is a poor location). Turn your mobile on, find Franklin or Lester on the contacts list and select the first item on the list (Mark Getaway Location). You can now walk away from the car.
Rewards for the completion of the mission: none
Requirements for the completion of the mission in 100%: There are no additional requirements for this mission so, it gets completed in 100% automatically.