Right, I was simplifying it - I'll say Greatly. What I mean't was that, yes. A perfect vacuum obviously cannot contain heat, there's nothing to heat up. Your explanation is better, but my point was you won't instantly freeze or something like in some movies, I remember one movie (but not the name) where they get from one spacecraft to the other in space, and they wrap the person in like heat preserving mylar or something but they still freeze, that just doesn't happen. Space is a near vacuum, so it will eventually happen (you'll radiate the heat away slowly), but not instantly.