[X] It's uncharacteristic for Rin, or any magician really, to accept that the condition just 'cleared up' and not examine it further, to ensure the recovery is complete and with no risk of relapse. And as a delayed effect of a momentary application of Satsuki's power? When Sakura spent the night with Rin and the last Servant in the war to still be unnamed, who is notable for being very reticent and secretive?
[X] See if you can discreetly inquire and prod at this cover story. No doubt they, or at least Archer, are prepared to deflect suspicion and shut down uncomfortable avenues of conversation. But it's worth an attempt, and to signal your own thoughts to Ilya.
-[X] If discreet proding of this story can't be managed, resolve to bring it up to Ilya and Deis later and politely converse with everyone.
You look back up at the Matou girl, suspicions running through your mind. Even a mage like Tohsaka wouldn't simply accept such a complete alteration without studying the subject in detail to make sure a relapse wasn't possible and that the 'recovery' was complete. She may simply be glossing over it as not suitable for breakfast talk - she didn't say she didn't give her an examination, after all - but she was sequestered throughout the night with the Matou girl and her mysterious Servant. The same Servant who is not particularly trustworthy and who actually has information regarding the shadow-thing and its ilk. Is she really stupid enough to think you aren't thinking she knows more about the disappearance of Angra Mainyu's taint than she's letting on?
"It's really gone from her, then?" The Matou girl looks at you and hunches her shoulders defensively. Tohsaka sighs and shakes her head before putting one hand on her sister's shoulder protectively.
"Well, I thought mealtimes were supposed to be conflict-free, but I guess that rule only applies when she wants it to. Sorry, Sakura." The other girl shakes her head mutely and Tohsaka glowers at you. "Servants can sense the Shadow - Illyasviel can back me up on this. Or would you prefer a blood sample?" Suppressing a scowl of your own, you shake your head and hold up your hands placatingly. Before you can defend yourself, however, the Matou girl clears her throat.
"Um … I know it seems weird, but, um … well, when - that - happened last night, the Shadow tried fighting it. That hurt and weakened it, and - and when I realized that Tohsaka-senpai was trying to help me, I was able to push it out. But if it hadn't been weakened, I wouldn't have been able to do anything, so -" Face red, she stands up from her chair and then bows toward Satsuki. "Um, thank you!" Satsuki's face reddens in embarrassment and she leans back, trying to hold her hands up protectively. Tohsaka nods, smiling.
"Yes, thank you." Satsuki's eyes flash nervously toward you as everyone else begins thanking her and you nod. She seems to relax, but it seems that such praise and gratitude is far from usual in her experience. The Matou girl sways a little as she straightens and moves to sit back down, but she waves off her sister's attempt at assistance. Her story certainly makes sense, and it would explain both the delayed reaction to Satsuki's ability and why the result was so pronounced despite the brief amount of time Satsuki was able to maintain it - without the connection back to the Grail, the shadow-thing couldn't overwhelm Satsuki's ability and the girl's true self was able to drive it out. And considering the look of surprise on Tohsaka's face when her sister was telling the story, it's likely that she didn't know about it, either. And if she starts to relapse, you can have Satsuki stay near her!
Tohsaka glances warily at you as you start getting food for Ilya and yourself, but you maintain your passivity as you wait for the atmosphere to drain a little. Ilya doesn't seem to care, though. "So, Sakura, will you stay with Rin after this? Or will you have your home repaired and stay there?" The Matou girl stares at Ilya, seemingly terrified of something, and Tohsaka comes to the rescue, putting her hand on her arm again to reassure her.
"It's been a cr- interesting few days, Illyasviel. I don't think any of us have really put any thought into the future." Ilya nods and returns to her vegetable-heavy meal, only to look up worriedly as you shiver in pleasure as you bite into a garlic-heavy piece of chicken. Tohsaka stares at you for a moment, too, then looks disgusted as you take two more of that kind of chicken. You really shouldn't, but …. "You like garlic?" You beam across the table.
"Of course! It's delicious and wonderful!" She sighs dejectedly and your glee and victory override your earlier defeat. You'll have to ask Meiling how much garlic is used in Chinese dishes; it won't matter much by then, of course, but it'll be good to know if she put it out in an attempt at poisoning you or if it's actually supposed to be there. "So, do you do anything for fun?" The Matou girl stiffens, surprised and nervous about being spoken to. "I mean, activities you do for fun, or because you like doing them." She opens her mouth but nervousness prevents her from speaking.
"She cooks, too, and she's in the archery club." You raise your eyebrows and grin.
"Oh, another cook! Maybe we should all get together and have a great cooking contest." Tohsaka's expression makes you giggle.
"I don't think we have enough space for everyone to cook fairly, Flan. And I think you all have different specialties, so whoever is judging would have to take into account the origins of whatever's being made." You pout at her and she sniffs and looks away. You stick your tongue out briefly.
"Fine, fine, no cooking contest. Hmm …. Oh, right. You haven't called Emiya yet, have you?" The Matou girl stiffens again. "He's probably very worried about you, so you should let him know you're okay." Tohsaka's mouth twists unhappily as her sister stares down at her plate.
What do you do?
[ ] Let everyone relax.
[ ] Discuss destroying the Grail.
[ ] Ask the Matou girl about Angra Mainyu.
[ ] Other?
DM Note: These are for after breakfast, which has not yet concluded; unfortunately, I have gotten around twenty words written in the past half-hour, and it's self-reinforcing at this point. :/