I didn't look at the page you linked to, but i would say that 1 and 2 are NOT the same thing. In my mind, 1 would be more like
2a) if Q then not P
going back and pondering some more...i'm not sure anymore. I think it sort of depends on what definition of "OR" you are using. By boolean logic, OR means one or both are true.
but generally in conversation, OR means a choice - you can have either one, but not both. If I present you with a piece of cake and a piece of pie and tell you "you can have cake or pie", most people would know that you can't have both, but must choose one of the two.
So, "I am working or I am on MD". in english, i think it means one or the other. boolean would mean both could be true - i.e. if I were a paid employee of the javaranch.
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors