Other mistake: When Jean Gamba goes to Jad Jamal's apartment right after Jamal takes the mask, he takes a key out of an envelope and puts the key into the lock and opens the door. He doesn't turn the key to unlock, he just holds the key. (00:48:45)
Other mistake: The photo of Silvia and her brother, walking on the road with guns in Africa, looks like a composite and is obviously a fake made up for the movie. The images of those two look flatter and have slightly different contrast compared to people in the rest of the photo; separate photos of them have been cut and pasted onto the road photo.
Other mistake: Towards the end, right before Sean Penn figures out that Nicole Kidman is in the safe room, Mo calls him on the radio, Sean Penn talks to him before activating the microphone.
Chosen answer: At this point, she has set her mind on killing the African leader and knows she'll likely be killed immediately afterwards (police, bodyguards, etc). She's writing her name in anticipation of her death.