I've been thinking about this one a bit since starting to listen to the Introcasts where the question is brought up about why Holly just pelted out of the Solar system and kept going rather than just getting to a safe a distance then parking up while the radiation died down. My theory is that Holly may have been acting in the best interests of the JMC at this point. With no living crew members around and needing to keep Lister in stasis, perhaps obeying some Robocop Directive 4 style secret program that even he was not aware of, Red Dwarf was sent accelerating out into deep space in order to hide the evidence of the accident. With Lister alive but in stasis, Holly couldn't allow the ship to be destroyed, but it wouldn't be in the interests of the JMC for a salvage crew suitably protected with radiation suits or using androids to find the ship and go poking around. First because they might end up getting billed for the costs of decontaminating, decommissioning and disposing of the ship (The latter two obviously wouldn't be in Holly's interests either) but also, once the crew files and black boxes are recovered the company might find itself being held responsible for the deaths of the crew (Afterall they did let Dennis the Donut boy blackmail his way up to Captain, under whose supervision an incompetent technician failed to repair the drive plate causing the accident), which could then lead to them being sued by the bereaved relatives and fined by the 23rd century's equivalent of the HSE. No ship, no evidence, no problem. It's just written off as an unexplained insurance loss and it gives the conspiracy nuts something to talk about too.