So I've just recently got this quest and was trying to do it. Turns out I already looted the crypt and used the key on the wrong statue, causing many problems. But I've managed to get by with the help of the wiki/console commands until now.
I've just gotten to the part where you break the boards and use the keystone I accidently used earlier, is there a way to get another keystone? Any help would be appreciated! Thanks.