Put your fingers in your ears when there's an explosion in addition to all the other things you were told to do. You have to crouch under a desk, you have to stay away from windows, you have to close your eyes. But in addition to that, you need to protect your ears!

In addition to all the steps you have to take to protect yourself, you can't forget that ears come in sets (せつ). You can't just stick one finger in one ear and have that be the end. You have a set of ears to worry about!