Y'see, the way she avoids Clinton's eyes in Panel 3 makes me think that no-one has ever offered Brun emotional support over this. It's still painful for Brun but I get the impression that someone has basically taught her that it is something that she keep away from social contacts because they don't want to hear about it.
All that aside, I'd really like to hear Brun's analysis of raisins and why she doesn't like them. The fact that it took so many slices to decide does suggest it was a fairly close outcome! 
She also avoids eye contact in the previous comic, quite obviously, focusing on the raisins as she answers those questions.
Analyzing from my personal perspective again: I avoid eye contact, in general, because it's uncomfortable, and because eye contact alone makes a creepy stare; there's a whole load of other subtle nonverbal behaviors that need to accompany it, and it's difficult enough alone to try to form precise thoughts and then form them into words. Add to that remembering what amounts to a complicated dance; add to it doing it in a way that communicates effectively to someone I am not familiar enough with to fully understand - and who I know doesn't fully understand me, and may get offended if I screw up - and then emotionally charge the subject on top of everything; and yeah, I'll need to put my focus on ANYTHING else just to make sure my verbal communication says what I want it to.
This isn't the case with all autistic people, of course - I knew a guy who was boisterous and gregarious. I'm probably more avoidant than most, hence my need to guard myself becoming so overwhelming that full communication is nearly impossible in these situations. (Notice, also, that she did make eye contact briefly when she felt the need to push back).
Also watch her eyes: her staring at the bread was pretty intense while under the 3rd degree, but in today's comic, once Clinton lets up and the situation defuses somewhat, she's still avoiding eye contact but not in a focused, deliberate way.
Now that you mention it I really want to hear this raisin analysis too!