Jane instantly gave a look at Elizabeth, which spoke her distress at such premeditation, and her intreaty that she would not give in to it. (chpt 55)
So Elizabeth is doing what Jane prefers. Though Jane hardly seems miserable when Mrs Bennet does succeed in her object:
Jane could have no reserves from Elizabeth where confidence would give pleasure; and instantly embracing her, acknowledged with the liveliest emotion that she was the happiest creature in the world. (chpt 55)
I think this is a situation where the anticipation for Jane was far worse than it actually turned out.
Perhaps Jane was also unsure of whether Bingley would propose, and scared to test it. If they were left alone and Bingley didn't propose, that could be quite heartbreaking for Jane, plus it would likely expose her to Mrs Bennet's comments again. We know Mrs Bennet's earlier behaviour over Bingley's departure pained Jane greatly.