[eesmith]

The linked-to text from the UDHR starts "Everyone charged with a penal offence has the right to be presumed innocent until proved guilty according to law in a public trial at which he has had all the guarantees necessary for his defense."

If your choice of definition were correct, that would mean that any firing which is part of a punishment would have to go through the court system first. Since that isn't the case, that means your choice of definition is not correct.

The penal code is "a code of laws concerning crimes and offenses and their punishment" - https://www.merriam-webster.com/dictionary/penal%20code . A penal offense is something which is counter to the penal code.