CBS has a partial transcript of the video, which identifies the bomber as an Abu Omar al-Musali.
"He will take advantage of the change of guards. We have been observing their schedule for a long time. This lion will then proceed to his target and we will take advantage of lunch time. He will storm the dining room where the crusaders and their (Iraqi) allies are gathered."
This email from a witness at Mosul indicates just why securing the base entirely is a hard thing to do.