Wow, I didn't even know that. That's a very wise way to keep power in such a precarious situation.
Trick is getting that person elected. Since he needs a majority of votes there are more people who may want a Liberal in that position than an opposition.
Assuming they even go for it. Having a speaker from your own party may have advantages in debates and such which you would give up for this scenario. There are lots of games that could be played in this situation. And it may be that they simply won't think of it. It has been my opinion that polititians don't always do the 'smart' thing. Of course if they were truly smart, they probably woundn't be running for office in the first place.