Emmeline and Richard build a raft for themselves and their child to escape the island. But why on Earth did they bring what they believed to be the poisoned berries???

I haven't seen it in forever, but maybe to kill themselves rather than starve to death?

Yeah, I believe that was it. If they felt at some point they weren't going to be rescued, they were going to take the berries. You're supposed to think when they're found that they're dead, but the person who checks them says they're just sleeping...big sigh of relief, the crowd goes wild, the end.