Ben reveals who the 4 people are when he is begging for his life. He says "if you kill me you will never know how dangerous these people really WERE!"

Past tense as in these people were dangerous in the past. He said the most dangerous people to the island were the Dharma people. Which means these people/Addnon/Frieghter are part of the original Dharma group.

See, I think the island is in the past -- and that this all already happened once before, which is how he really knows...

I thought he was just implying that, "if you let me live, in the present moment, I can tell you who they ARE"
but-

"if you kill me, you'll never know"....kind of thing.....

does that make sense? I think he was just trying to use correct tense in his grammar.

although, it is LOST.....i could very well be wrong.

Its funny, my sister picked up on the "were" part tonight.
Its odd because Ben was implying they would cease to be a threat if Ben died, which isn't much incentive on their part to help him stay alive.

I thought Ben saying 'were' was kinda strange too. I havent had anything useful to add though.

This is already being discussed here:

http://www.thefuselage.com/Threaded/showthread.php?t=87902