The Visitor Event Guide/Discussion.

I just found how to avoid dying from the bombs!!

basically, the bomb explodes at your coordinates, but if you are moving fast enough, you can outrun the explosion; most of the time anyways, and have it hit air. As I assume you have noted, the bomb timer starts the moment you get blocked. If you keep getting repeatedly blocked, you wont explode until there's a stretch where you're not and the timer reaches 0. So what you have to do is, after you are unblocked, attack 2-3 times, depending on your attack speed, and run to one side, while having jump key held down to give you more speed. Most of the time the bomb will explode a bit behind you and you'll survive.
You have to do it every time you get blocked though, and be careful of timing it right, so that you don't run into the wall before it explodes.