Hi Chuck,
You definitely want to avoid metal chips getting anywhere inside the MDR / HDR. There is a large amount of information on the MDR / HDR in the database
here. You can either completely dismantle the case (which is the route I took when I did it), or, if you check the exploded diagrams from the link above, it looks as though it may be possible to actually remove the back panel from the main chassis. If possible without major dismantling in other areas this would enable 'surgery' to the rear panel without fear of stray metal chips getting where they shouldn't...
Regards
John