If the opposition does not force an election, then the will have given up a lot more power

Travers: They used to behead kings for what Harper is doing - thestar.com
If the opposition parties do not vote to hold Harper in contempt for not releasing the Afghanistan-related documents regarding the torture scandal, then they are basically handing over their power to the prime minister's office and saying that they are answerable to the prime minister and not the other way around (as it is/is supposed to be).