Hari Sauri: In the morning, as usual, Prabhupada went upstairs right after his breakfast to take his nap in the sunshine. I escorted him through his rooftop room onto the back portion of the roof and left him lying comfortably on a mattress. I decided to go back down. If Prabhupada needed me he could simply ring the bell; I would hear it and respond immediately.
After some time, I started to think that Prabhupada seemed to be resting a little longer than usual. I was waiting for his call, but the bell hadn't rung.
Maharathi dasa, a visiting devotee from Germany who is staying in the guesthouse, suddenly ran from around the corner of the guesthouse stairs, angst written all over his face. "Hari-sauri! Hari-sauri! Prabhupada is trapped on the roof!"
I went into instant shock, and I knew immediately what had happened. When I left him to sleep on the back section of the roof, I had returned through the room, shut the screen door behind me and in a stupor of automation slid the bolt, locking it from the inside.
Prabhupada hadn't rung the bell on his desk, because he couldn't. He had woken up, and when he couldn't get into the room he had to wait on the roof for nearly an hour before Maharathi happened to look over from his guesthouse room. Signaling his attention, Prabhupada shouted to him, "Find Hari-sauri. He has kept me prisoner here!"
I simply apologized. Prabhupada nodded, said no more about it and, because it was already 11:30, repaired to the back garden for his massage. So far as he was concerned, it was over.
Reference:A Transcendental Diary Volume 5 - Hari Sauri Dasa