The Bloodmoon strikes randomly but luckily you will get a brief warning ahead of time to prepare. This means you can either stay to fight or quickly find shelter.
If you happen to be stuck outdoors then torches may not aid in your fight. While they will provide a bit of light, most of the land will be drenched in red darkness. It's very difficult to see any distance and mobs are merely shadows in the night.
Even worse is the fact that during the Bloodmoon you won't be able to sleep it away. And on top of all that, mobs will be instantly drawn to you as soon as the moon rises. This is truly a fight or flight situation depending on how well equipped you are.