To know if something is spoiled or molded. To make sure that it wont give you the stomach virus or food poisoning.
To keep yourself and the omelets safe, you should break the eggs against a flat surface or against each other to create a large enough crack so that the eggshell (small pieces) don't fall into the egg itself. The risk of the eggshell in the omelet is that you could possibly be giving yourself salmonella which is a dangerous situation.
Lactose glucose molecules joined together form