Go to floor 2 and find a safe place to start the heist.
You can't enter the door because you need the key. Quickly find the guy and open this door. The guy will be at random places.
There are 4 drills to be placed. Make sure 2 at the panic room and another 2 players at the room below the panic room. It will be quicker to finish this job.
Defend the area and look out for drill until it finish. Once a while it will stop and you have to re-start it again.
Then, wait for the explosives at the roof.
Always be careful here. It will be more police, snipers and special forces. Stick together with your team. You must eliminate snipers to proceed.
This C4 bag drop at the random location. It depends on your luck :p
There are 9 C4 place to set up. Divide it to each of your team member. It shouldn't be hard. As always, stick at least two people. You will never know when the special forces will come and knock you out in a sec!
When all the C4 has been planted, now move to floor 2. It will automatically exploded.
Now, get back to the roof.
You have to clear this area.
Then, try to attach the magnet at floor 4. Move together if you wants to be safe.
Then, just defend the helicopter. It will be done after a while.
Now, quickly escape! You have 4 minutes to get away.
Go here and the mission will end. [Mission Completed]