I think it will last longer that.  If the BC Liberals put up a speaker, pretty stable, but if not much closer so you are right about the risk.  But after losing a majority the party will dump Clark and until a new leader is in place they will make sure enough members miss each confidence vote so the government doesn't fall as they know it would hurt them in a general election.  However in 18 months or more once the BC Liberals have a new leader all bets are off.  Mind you it can go both ways too as there will be times when they have a more comfortable edge due to absent BC Liberal members, but certainly an absent NDP is problematic.  The real danger is any future by-election in an NDP or Green riding and if the BC Liberals flip just one in their favour its over and in fact I don't know the exact rules but they might even have the option to form government without an election since they would have a majority.