This became an ordeal. When I left my bags with the bell captain that morning, he explicitly told me as long as I was back by 11pm, I would be good to go. I arrived just before 11pm (confirmed by the clock prominently posted at the bell station), but the security staff said he had gone already and told me tough shit. I had to find the night manager and have her call the bell captain back to his post. Apparently there wasn't another soul alive with a key to the storage room.