I've made my share of safety mistakes -- like leaving change on a hotel nightstand where my 3-year-old son Nate could reach it. He swallowed a penny and we spent five hours in the local ER. (He passed it without harm the next day.) That was the last time I've let loose coinage linger, but I'm bound for other blunders down the road -- all moms are. "Nobody can watch a child at every moment," says Robert Sege, M.D., a professor of pediatrics at the Boston University School of Medicine. But that doesn't mean it hurts to step up your game. Check out these seven situations that can turn frightening in a flash -- and learn how to keep them as uneventful as possible.