From memory, Beth is still 3 or 4 eliminations away from being out. Eva and Izzy both return to the competition at a later point, one very briefly. And I think Leshawna made it to the final 5, so she'll be around a while.
She did, the order was Leshawna>Duncan>Heather>Gwen>Owen
The writers didn't really have a good way to get her out because she was competent and likable by everyone else, so they had her get voted off by accident. It's dumb, but better than the way they originally intended with Leshawna being voted off... for giving her immunity to Gwen? In the cut alternate episode, even Gwen voted her off because Leshawna was too nice, apparently. The writers also said they intended her to win originally before settling on Owen and Gwen.