11/23/2009 at 01:00 AM EST
> The British star, 37, gets all wet in the new end-of-the-world film–but admits to being skillful when it comes to diverting disaster at home.
HOW ARE YOUR SURVIVAL SKILLS?
When it comes to my kids [Ripley, 9, and Nico, 4], I could literally pick up a car because my protective instinct around them is fierce.
YOU GET SERIOUSLY SOAKED IN THIS MOVIE.
I spent a lot of time incredibly wet. I was fully clothed and submerged in a water tank for three days. It wasn't hard, but I'm a little girl about that sort of thing.
DO YOU ENJOY DOING YOUR OWN STUNTS?
I love to show off my girlpower! I'm willing to get physical, but I'm practical. [With] two kids, I don't want to risk injuring myself.
HOW DO YOU PUT OUT FIRES AT HOME INVOLVING YOUR KIDS?
I absolutely don't believe in punishment. We always talk about our problems. I don't care how long it takes, we just talk it through. Otherwise it just escalates.
MOTHERHOOD VS. STUNTWORK: WHICH IS TOUGHER?
There is no comparison! I absolutely love acting, but being a mother is the greatest role and challenge. It never stops, but the satisfaction and the joy I get from it make the effort tiny.