What would a normal person have to be looking at to make that expression? Someone brings in your surprise new Lamborghini? Someone makes your paralyzed dad walk again? A new swimming pool was built and finished in your backyard? The TV is showing the powerball numbers and they all match your ticket? Your spouse was missing for a week and feared dead, and he walked in the door, perfectly healthy?
I think post 5 explains her expression.
That one would do it.
Especially if you were certain that even if he survived the fall there's no way he could climb back up that cliff! ;^)