I think that the cloister bell didn't start ringing when the TARDIS was exploding in 'The Pandorica Opens' because River Song was in it and the TARDIS had put itself into a loop to save her, so the TARDIS was unable to do anything else, or to change anything (including events and sounds).
83.85.28.232talk to me 12:50, April 9, 2013 (UTC)