To be fair, I do believe that in extraordinary circumstances a Prime Minister should be able to pass over his own MPs and put non-elected people into Cabinet. If Canada was at war and nobody in the House knew anything about the military, it would make sense that the PM be allowed to call up an expert on the Canadian Forces and have them join the Cabinet.
Or imagine being Stephen Harper and you wake up the morning after winning a general election only to realize that the vast majority of your MPs just aren’t smart enough to be in Cabinet.