Will my tacky polyurethane eventually cure when average air temperature rises?

So, for lack of a proper shop, I was applying a first coat of undiluted Varathane Ultimate Polyurethane (oil based) to a plywood box using my dining room table under a plastic drop cloth as a work bench. The room was about 75F. The family came home and complained about the smell, so the drop cloth and project got moved to the garage where the temperature was 60F. The next day, I snuck the project back inside and hid it in a closet, once again at 75F. Six days later, the finish is still tacky to the touch.

I’m going to wait until it gets warmer in the garage (several months from now) before attempting any more coats of polyurethane, but I am curious whether I have damaged the current coat such that it will never cure. …and if this is the case, that the existing coat will never cure, how do I remove it before starting over?