No, opening a microwave oven before it beeps will not release deadly microwave radiation. Microwave ovens are designed with safety features that prevent them from emitting microwaves when the door is open. When you open the door of a microwave oven, it automatically stops producing microwave radiation. The purpose of the beep is to alert you that the cooking cycle has completed and it is safe to remove your food. However, it's always a good idea to follow the manufacturer's instructions and exercise caution when operating any electrical appliance.