I would run it if it's in good condition.
A friend of ours rented a small apt. in Newport Beach, CA, that doesn't have air. She bought a portable air unit at Costco or Sam's and had the maintenance guy install it.
It is SO nice and blows very cold air. They had to put a panel in the sliding glass door so that the vent hose could exit. Very nice install, you don't even notice that the sliding door is not closed all the way. Being on the third floor, security is not an issue.
You might want to think about a portable unit to add to your exiting unit.
Safe travels,
MM.