Can't we just put a human in the box, and do same thing except without the poison. Inside of the box, the human will either see the hammer smash a vial, he won't see the hammer smash the vial or he will feel like he saw both things happen. The time t' starts when the hammer is expected to drop or not to when the observer opens the box. We put a clock inside of box and tell the subject to remember what happens during time t'. Won't this at least rule out or conclude that he was in a superposition?