Dinner malfunction

My favorite thing for dinner is a delicious tender roast that's been simmering all day making the house smell yummy and inviting. So at 5:30 tonight as I was on the couch with Addison I hear a loud *POP* and I went into the kitchen to see what happened. Here is what I found. I started it at 10:30a.m. on high then at 1:00 p.m. turned it to low.  It blew up at 5:30.

 How do you return something like this to the store?  I'll be doing some calling around tomorrow.

 This picture was taken a few hours after the incident so the roast is really dried out- it wasn't burnt.

Needless to say, we ordered pizza for dinner.  Unfortunately not one with homemade roast beef on it.