For Cathy's cluck, is the fact that the kitchen is locked important like during a party the DIK's close some doors or it's just a way to say we can't explore ? Because if it's locked, only someone with the keys could do it so a DIK (If we think that they did pass by the kitchen to go to the library). But there is a point which is strange about the library and the kitchen, we know that Rusty found the PC in the library, so why is Nick searching in the library when others DIK know that the PC was in the library ? This point become more important with the fact that John Boy is waiting for the WC, so he should know that Rusty did go in the library. Nick shouldn't need to go in the library unless he was already in it and was hiding when Rusty walked in. John Boy or Riona could know who passed by the kitchen if they were already in this corridor.