There is no way they have to stay for two years. Serve the landlord the proper notice, see the PRTB website for the correct time periods and maybe speak to the PRTB, that's what they are there for. Based on the actions of the landlord they need to be really carefull when leaving, the property should be in the same cleanliness as when it was rented, apart from normal wear and tear, and take pictures of how they leave it in case there is any dispute about the deposit.