The CIA authorized us to go on with this mission in exchange of the data and the access codes. This is going to be your last operation in this campaign, and certainly the most critical and dangerous. You have to go down in Mexico and terminate the activities in Tolan's secret weapon factory, and also save some of your wounded team members that are held as prisoners down there.  

It is not as simple as it may appear; they have an intercontinental ballistic missile that they were making for Iraq and we fear that in a desperate act they might launch it. Unfortunately, if they start the count down, it is impossible for us to prevent the launch without the password.  If they have indeed started the count down, the only thing you can do is to change the target of the missile. You would have to change it to the factory itself. To achieve this, you need to find the launch key and change it from the main control panel.

These are the steps you have to follow:

1. Find the key.

2. Go to the missile and change the target to the factory.

3. Leave some man behind to prevent anyone from changing the target or launching the missile.

4. Save the prisoners.

5. Get the hell out of there (because it's all going to blow). 

No guards or workers should escape; you or the explosion should eliminate them all.  Use a silencer and don't give anyone the time to alert the others.

Good luck!