Here is a question for ya

[mtj]

How did Rousseau survive the purge?
My guess is that Ben went to her, told her about it and gave her a gas mask, in deference to the fact that she was Alex's mother.

[Thor Twain]

How did Jack, Kate, Hurley, Sawyer, Juliet, and Sayid survive the Purge? If they're there when it happens, how will they survive it? Or... will they survive it? Will they stop it this time?

[annsensei]

what year did the purge happen? danielle and group don't arrive until 1989. sawyer and friends are now in 1974-1977. I hope they're not still there when the purge happens. maybe the purge happened before danielle's group arrived.

[Thor Twain]

1992, according to Lostpedia.

[mtj]

How did Rousseau survive the purge?
My guess is that Ben went to her, told her about it and gave her a gas mask, in deference to the fact that she was Alex's mother.

Ah, the old answer a question with a question schtick.
I don't think the Losties are still going to be in Dharma time when the purge happens.
I do think their quandary is going to be what to do about young Benjamin Linus.
And Faraday will tell them that they "can't alter the future" so they will decide to let lil' Ben be.