No, Lelouch isn't stupid. But he is still, thus far, enslaved by his emotions for those he cares about. This can contribute both to his willingness to protect Suzaku/a major enemy and his livid rage at having his beautiful plans thrashed so easily. I think he wouldn't have been so pissed if it hadn't been Euphemia because of his feelings for her and his trouble with easily removing people he cares about. I predict he will try to talk sense to her, and that will be the start of much badness. I think his anger will get the best of him. Anger makes Lelouch sloppy.
That scene will forever be symbolic of Geass' love for crack... and pizza.
(no subject)
That scene will forever be symbolic of Geass' love for crack... and pizza.