In "The Pit and the Pendulum," how does the narrator manage to break free from his bonds? What are the first two dangers that he faces?

The first two dangers the narrator faces would be the pit and the pendulum (the story is aptly named). Because the room he is trapped in has no light at all, he stumbles around in the dark, feeling his way along the room, until he falls face-first to the ground. When he is lying down on the floor, he notices that his forehead and nose, though his face is angled down, are not touching anything. That is when he realizes that there is a pit in the room, which he tests the depth of by throwing a piece of the ledge into it. Next is the pendulum, with its ever lower swings, threatening a slow and agonizing death. He does face other minor problems, such as the drugged water and the rats eating his only food, but I would not consider those true dangers.

After being drugged by the water, the narrator passes out, and when he wakes up, he finds that he has been bound to a platform of wood by a strap that encircled his body and limbs, save his left arm from the elbow down and his head. He struggles to release himself, but in the end, he only manages to escape by rubbing his remaining food on his bandages and falling still so that the rats come and chew straight through them.