this isn’t legal advice and im not your lawyer, and I don’t know anything about real estate law since i haven’t studied proeprty sicne the bar exam, but what about making that a condition of the lease — something like, “In the event that the lessee enters intoa sales agreement and closes on a New Residence (define residence as whatever it is you’re looking to buy), upon providing proof to the landlord of the purchase of the New Residence, and the lessee actually moving into the New Residence, then the lessee shall have the right to terminate this lease with no penalty and the seller shall return the security deposit to the lessee.”
then you can tell the landlord, hey, im probably not going to buy anything, but i might try,a dn i just want to have this as an option? it probably wont disturb the landlord too much — but i guess it might.