You only have a single cr_shiftmembers object, but you have multiple sc_users. You are iterating the sc_users to copy a value into cr_shiftmembers. This will only hold the value of the last iteration of sc_users.
I think you need to change how you show the data. Instead of starting from cr_shiftmembers, use a datagrid that uses sc_users as the data source. This can then retrieve values from cr_shiftmembers by association.
Good luck