I'll agree that Richard and Stephanie should have been more adult about it.
BUT, Lisa should have risen above it and not show that it bothered her. Oh, wait, EVERYTHING bothers Lisa. It's all about how she can negatively react to each situation. The permanent scowl, the constant complaining, ugh! Enough already.
It's the FIRST time Richard and Stephanie have acted anything less that totally professionally. It's not the first time Lisa has behaved like a spoiled child. To me, that's the reason why Richard and Stephanie didn't act like they were happy she's in the final three. Because they're not, and they're so tired of her negativity, that they don't care if she knows it.
Again, just my opionion, based on what I've seen of the show. I'm sure it's all edited within an inch of it's life, but I can only judge on what I've seen.