Lost E4 The little prince
 

Who was that chick at the end and why was Jin surpised to see her?

oh yoox. that was danielle. Alex's mom. The crazy french woman that came with scientists. she was there for 16 years. sent out that message on the radio tower. yep

It was the chick that sent out the distress calls,kidnapped Aaron and Sayid, and blew up her own home in S1, she's not in much of the rest of the seasons.

and he was surprised because he wasn't aware of the whole time travel thing before that incident.