Look at the last photo. That shows her realizing that she can't get to her family before the wave does. Others have said it was her being exhausted, or showing frustration. IMO she is showing resignation and defeat.
Concern for her own survival was never a consideration. Her only thought was for her children. None of them understood what was happening when the water went out - the father and children followed it out in wonder. Then, when they finally realized that the incoming wave was a threat, it was too late for any of them save the mother, and she just ran for her children.
This set of picture troubled me all night. Even those familiar with earthquakes have trouble realizing the threat of tidal waves. See my post her about my mother surviving a tidal wave following the 1964 Alaskan earthquake: http://www.freerepublic.com/focus/f-news/1309724/posts?page=112#112
My mother grew up lived all her life within ten miles of the San Andreas fault - generally within 4-5 miles. And her mother, as a girl, was shaken out of bed in San Francisco by the 1906 earthquake.
The family in these photos had no chance whatever of survival when they did not immediately sprint for the trees when the water went out, and little chance even if they had. I've seen the videos of the tidal waves hitting this beach. The children were just too small to survive in that rough water, or climb the trees, and their parents would have clung to them until the end.
From the picture I posted in 288, it looks like the people who ran off the beach would have been able to run up a sharp rocky incline immediately. I would guess that, other than this poor family of six, everybody else on the beach survived OK. We can be sure the photographer did at least.