Timestop is "flashy," if Homura takes the steps to engage it people will notice. I suppose that she could excuse herself... So that's not implausible.
Goals:
Convey "don't spread witchbomb" with Mami sitting right next to us
Reassure Hitomom
??? (Situation is evolving)
Train of thought: we're going to have to imply what we know alongside the fact that not everyone else knows. Easiest way to do that is "we know things." Easiest way to do that is the brief origin story. Easiest way to imply everything, I think, is just to diss QB out loud.
We can probably trust her not to bandy the witchbomb about freely, of course, but...
Here: the "too specific" version
[] Broadly and unspecifically diss Kyubey.
[] Madoka and Hitomi are uncontracted, and will hopefully stay that way.
-[] Madoka and Sayaka were contacted by Kyubey initially. Some of the social results were... Awkward, for Hitomi. At that point, completely excluding her would have been considerably dangerous. Better to give her some information and not all than to have her start following people around unprotected, or making contracts to help.
--[] Pointed looks on "some information" and "not all."
Here: the "we should probably do this" version
[] Broadly and unspecifically diss Kyubey.
[] Madoka and Hitomi are uncontracted, and will hopefully stay that way.
[] Sayaka and Madoka were contacted (NOT contracted) by Kyubey. Partially informing Hitomi was necessary for her safety once the social consequences began to distance the two from her. Too much information has a tendency to be just as problematic, unfortunately.
-[] Use this to imply to Hitomom that ffs don't talk about the witchbomb.
We probably want to talk about cleansing sooner rather than later, though. But I have class.