Movies are not made to represent martial arts. They are made to make money. I seriously doubt most of the techniques used in aikido would translate well on film.
I can't think of too many movies that have ever really represented a martial art very well...
As for the original question, I'm not too sure. Like most people in the entertainment business. I would guess he is using a variety of techniques, to make for an appealing fight scene. Keep in mind he's been involved with martial arts since like the 60's - I'm sure in that time frame he's trained with all types of martial artists. To think he hasn't picked/used some of those techniques in his lifetime would be silly.
-Rob "Who freely admits, he admires Seagal, but thinks his wardrobe stinks!"