Twice it happens that he is asking a ridiculously long question, she starts to break in but he continues talking. Whom are you counting as the interruptor here? She is the one formally interrupting, but he should cede because his job is to make her talk.

If you count him as "interrupting" merely because he's doing the wrong thing in the context, then interruption-count is no longer the objective measure that it was introduced as. (More generally, it seems difficult to use interruption-count in a context like this where the two interlocutors are not intended to be in a symmetrical relationship to each other.)