I start fires and hot romances, what am I?

Step foot in me, you are six feet under. You may come to me when you hear whistles, sirens, and thunder.

Why was the guy who was hit in the head with the can of soda lucky?

Twenty horses race at a steady pace, never breaking, never overtaking. Children laughing, children cheering. No losers here, everyone's winning.

It lies puffy on your bed or folded neatly in a cedar chest. In Australia, a doona, in Indonesia, a bed cover, in England a continental quilt. Someone who soothes you when you are sick or sad. Start with three letters that commonly follow dot, then a place of strong walls filled with defenders. Finish with an uncertain interjection.