The Cowardly Lion
1. He genuinely feels Duceppe is a coward. After all, Lapierre considers the BQ nothing more than a "temporary ad hoc rainbow coalition" so it must be baffling to him how anyone could turn down a chance to be Premier of Quebec for that job.
2. Jean Lapierre is absolutely devastated that Duceppe didn't jump provincially. This is the theory I subscribe to. Here's what I wrote about Jean Lapierre's speech at the LPCA convention this January:
He mentioned that Stephen Harper would not be able to break into Quebec (wow! shocker!) and that Gilles Duceppe will leave to become leader of PQ (I believe Lapierre said "Premier of Quebec" which is not how I'd be wording it if I were a Jean Charest supporter). It sounds to me like the Liberal's Quebec strategy consists of hoping Gilles Duceppe leaves federal politics and I'm not sure if this is really the best way to win back the province. But, then again, Jean Lapierre is a political genius and I'm not, so maybe it's not such a bad idea.
Lapierre has been basing his entire strategy on the departure of Gilles Duceppe and now he realizes this isn't going to happen. This is also going to make the Liberal line about "The Conservatives in Bloc are in bed" a lot harder to push, because that entire theory was based on the premise that an early election would allow Duceppe to jump to Quebec City and win a referendum.
3. Maybe Jean Lapierre was hoping to throw his hat into the ring should the job of BQ leader open up ;-)