Ah ok, then this book probably wont help. I dont think it goes into that much, but just for kicks its called Universe 7th edition by Freedman and Kaufmann III. its really good.
Making an educated guess id actually think that there would be very little actual 'motion' due to the pressure untill the collapse. THat is up untill the point where the QM properties are overcome id think the shells would be in more or less the same place