Natalie already knew about the curse placed on Barnabas by Angelique; Joshua told her in #449.
Did Joshua give Natalie any details about what Barnabas's curse actually was? It may be that she wasn't aware that Barnabas was involved in Josette's death until she put two and two together in the Tower room.
[spoiler]If I remember correctly, Natalie did tend to Millicent after Barnabas bit her, but it may be that Natalie didn't know exactly what had happened. Perhaps she was given to understand that Millicent had somehow been adversely affected by Bathia's efforts.[/spoiler]
The scene in the secret room of the mausoleum was just a little bit odd. Ben was trying to keep Nathan from destroying Barnabas. And yet Ben had tried to destroy Barnabas, at Barnabas's request, and had been unable to do so. I guess that Ben understood that now Barnabas did not want to be destroyed - but Ben didn't understand why. Ben didn't understand the whole time travel thing. Ben knew that Joshua was planning to destroy Barnabas, and as far as Ben knew, Joshua hadn't changed his mind. Was Ben planning to stop Joshua from destroying Barnabas, too? It's all very puzzling. Of course the other question is:
could Nathan have destroyed Barnabas?
I enjoyed the part after Nathan was killed and Natalie faced Ben alone. What a horrific, unexpected situation for her! She had thought it would be so easy: simply go to the coffin and have Nathan kill the vampire during the day - a consummation devoutly to be wished. And now she was in danger of her life - and now she was dead. By rights, her ghost should be haunting that secret room.
We got an interesting statement from Barnabas, and I thank the Robservations for the exact wording: "I'd rather live for eternity trapped in my coffin than live as I must here." He spent nearly 200 years in that coffin, and it practically drove him insane, and one time in 1967 he pushed Julia's face into the coffin and told her he wasn't going back. Something like that. So now here Barnabas is, knowing what it was like, and saying: "I would rather be imprisoned."
I just love it when the chains appear on the coffin. But the crying of Josette's ghost never works for me. Oh, well, you win some, you lose some.