Let's say you are in the middle of your Shemoneh Esrei when and all of a sudden, the situation becomes yichud. What may you/must you/should you do?
I know the very-basics like "don't interrupt one mitzvah for another" and "positive mitzvot [sort of] overrule prohibitions" etc., but these did not seem to shed much light. It seems from the antecedent of footnote four here that we treat all matters of yichud as rabbinical mitzvot today. And here (and based on other knowledge) it sounds like we don't usually interrupt tefila for other mitzvot, even Torah study (=Biblical.) Thus my instinct is to say that we do not move from the Amidah to get out of yichud. But possibly the safer answer is "Be so absorbed in your Amidah that you do not notice whether you are in yichud or not."
Cases: 1) Someone with the maximum level of obligation in that shemoneh esrei 2) Someone with the minimum, i.e. a mother davening maariv, or a tefilas nedava; A) Really serious yichud situation B) Something borderilne
(Not sure any of it would make a difference, as one is nonetheless standing before the Holy One, Blessed Be He, and by some natural principle we don't interrupt that)