How the two women at snow berry's place torture Oliver?

Oliver was made to sleep in a cupboard among the coffins.

'Then come with me,' said Mrs. Sowerberry: taking up a dim and dirty lamp, and leading the way upstairs; 'your bed's under the counter. You don't mind sleeping among the coffins, I suppose? But it doesn't much matter whether you do or don't, for you can't sleep anywhere else. Come; don't keep me here all night!'