Well Suzaku was sorta all 'I'm gonna take revenge now' after Charles and Marianne poofed but then Lelouch was all 'So what? >:|' so I'm guessing Suzaku realized revenge wasn't really the answer? -specualting-

I was close to dying of laughter but it's the closest thing Suzaku's made to a smile compared to the other episodes. xD; I think he's smiling for other reasons too-- -shot-

I think so it's easier for the animator? Like with the school uniforms.