You cannot "duck" in Far Cry 2, at least if you mean crouch. You can only go prone or stand up.
"far cry" is used to denote difference in degree, or between ideas or qualities. One would never use the idiom in reference to actual distance.. "It is a far cry from astubbed toe to an amputation" or even "It is a far cry from Brooklyn to Broadway". The two geographic areas are quite close, of course, but success in Brooklyn won't guarantee success on Broadway.
Just press the key under Esc. which = ~
There are quite a few hacks and cheats out there that show you how to get infinite diamonds for Far Cry 2 for PS3. However all of them are fake. Only infinite ammo is possible to get.