I was recently cooking and made a lemon juice and oil dressing, It was sitting in a small bowl for several minutes when it suddenly exploded. It was a small glass Anchor custard cup, I put the juice from one lemon, 2 table spoons of olive oil, and about 2 table spoons of diced green onion with some salt and pepper. It sat there several minutes while prepared the rest of my meal then suddenly exploded for no reason at all! Any ideas what happened?