Hmph! There are precedents for these Jihadis being pretty doped up by the time their final moment arrives. Makes sense. It sounds like the guy was quite zoned out after the device went off (and probably before). Most folks would be screaming bloody murder with that going off in their lap.
If you're going to go to the trouble of financing, and planting a guy like that on a flight, you're going to want to make sure he carries through on the project. It is a small matter to load the guy up with “pharmaceutical courage”, and make sure he doesn't forget his religious obligations.
Of course, the guy could have been just plain psychotic. There are such people in the world, and some of them are Muslim Jihadists. Crazy? Yes. Gutsy? Mostly not, IMHO. It would be interesting to see what the drug panels are for this guy. In Iraq, at one time, they were doing drug testing on suicide bombers. There were quite a number of them that were pharmaceutically “under the influence”.