"Ah..ahah..." Shirou felt silly now, especially when this lady was talking about her the way that she was. So she reacted to her little 'defense' too, did she? That must have meant that Marisa had magical potential within her too... Admittedly, the change of topic (though he didn't want it to shift to this in the first place) meant that he had forgotten about her egg request for the time being as he lightly bowed his head and glanced to the side. Another deep breath later, and he had his composure back.

"Sorry about that," he apologized like it was natural of him. Even if it wasn't even his doing. "That bounded field is a simple but effective one."