Whoa! Chill, dude. Modifying the terorists' behavior is not that big of a deal.

Just edit the templates for the terrorists.

Here's an example:

The template for the terrorists that hold the hostages in the Subway Station level of RS3 BA is: Sta-HostageHolders.tpt

It looks like this:

The attributes Coward, Deskjockey, etc., through PSniper always add up to 100.
So, the number for each attribute represents that percentage of their temperament. In this case the hostage holders are 100% hard ass MFs.

The attributes RndVariation, Assault, Demolitions, etc., through Observation are for skills and other behavior (~intelligence). These are more like points and do not have to add up to 100% collectively. Each is on its own scale from 0 to 100.
These guys may be hard asses, but they are weak on observation. (Easy targets? )

Here's another example:
The terroists that carry AK-47s and Molotovs are defined in the template: Sta-N-AK47-Mol.tpt

Notice the number in front of each weapon listed: 025 and 075 add up to 100.
I believe this may be the percentage of usage of each type of weapon.

This type of terrorist is a hardened suicide bomber and has better observation skills and self control than the hostage holders above do.

Changing these attributes can modify the behavior and skills of the terrorists in the game. This is one of the ways UbiSoft ramps up the difficulty as you proceed through the game. The thugs in Rocket Facility were definitely tougher to combat, as I recall, as compared to the guys on Subway Station.