BELLEFONTE, Pa. — One at a time, the pledges of Beta Theta Pi walked through the doorway and were handed a bottle of vodka from which to chug.

Timothy Piazza, a 19-year-old sophomore from New Jersey, grabbed the bottle and turned it upside down, taking a long swig. It was one of his last conscious actions, and thanks to the fraternity’s surveillance cameras, it was on full view in a courtroom Monday not far from Pennsylvania State University, where lawyers, spectators and more than a dozen of Mr. Piazza’s fraternity brothers watched what happened, and did not happen, next.

Mr. Piazza staggered through a kitchen, the top half of his body flailing as if disconnected from the bottom. He tried to leave the fraternity house, but was unable to gather himself enough to push open the front door. At one point, not captured on video, he apparently fell down a flight of stairs.

Gasps went up from many in the gallery as they watched Mr. Piazza’s fraternity brothers drop his limp body on a couch, sit on his legs and jam his arms into a backpack filled with books, to keep him from falling over and potentially choking on his own vomit.