Now this would be interesting fight. I could see these character interacting and talk about morality. They would talk of who suppose to be the bad guy in this battle. Forget the battle to the death I would like see which one can persuade the other from changing their life goals.
Rulk is in no way dodging freezes attack he going to hit much sooner than later and lets say he got himself hot enough to resist the cold gun directly captain cold should set up a few fields for him to pass through bringing his temp back down before letting him cop as well as slow him down as the cold slows us all down its potentially a one hit win at Rulks end but tagging captain cold is by no means going to be easy. .... if we wanted a more evidence based answer we need to dig up flashes temp when he using speed force and then get data on Rulks average heat level when he gets ticked.