I know that.
The problem is that in theory, until Bill C-24 is repealed, leaving for another country later could be used as evidence that, at the time of taking the oath, the applicant hadn't originally intended to remain in Canada and therefore misrepresented himself.
Nobody has ever had their citizenship stripped under this provision of C-24, so it's hard to know how it would be applied. But the possibility that things would play out as I describe was one of the major arguments against this part of C-24.