Oh my! I just have this vision of exploding mac and cheese and have to chuckle. I think I would have had a puddle too. Doesn't look like it will take much to fix it. I'll have to remember this because my husband is forever using our thermos and he just leaves it sitting on the counter. So from now on I will at least loosen the lid when I see it sitting there. Since there are just the two of us like you I don't always get to the dishes when I should and they sometimes sit.
PS. Thank you and your husband. My cousin is in the Army and has been deployed twice to Iraq. It is hard when they are gone and I just wanted to say Thank You for being a Military wife.