And all this is saying is that they cannot be arrexted while Congress is in session, it says nothing about afterward. And in any case, that is irrelevant, leaking classified information is a felony and they can be arrested for this at any time.
As far as not being questioned in "any other Place," that only applies if the offense occurs during a speech or debate in Congress, this offense didn't.
bump
I can't ever remember a Senator being arrested. Do you?