Yet one more idea, before the final season of Lost begins (also, just in case it turns out this is what they're doing anyway).
Disclaimer: I haven't even seen a single full minute of Lost.
They should find a contraption deep inside the Island, that takes them back in time. To the first season. Then they should proceed to try and scare themselves off from a much more dangerous enemy, while remaining unseen. This will handily explain all those weird dinosaur noises and nonsense from the first season that they... appear to never want to explain.
