If you are only needing to cut a couple of boards, just use a hacksaw with a bi-metal blade in a well ventillated area, and wear a dust mask and goggles. A quick file to size will get the job done. The blade will wear quickly, but will do a few boards without trouble.
No matter what you use, unless you are willing to spring for a guillotine, you will have loads of really fine particulate dust to contend with. This gets into your clothes, and settles everywhere, so wear something appropriate. The thought of using a dremel as a saw for PCB laminates conjures up thoughts of "lung trouble" to me. Plus you have stated that you only need to cut a couple of boards, so there's no financial benefit to buying anything specialised, including the dremel, unless you plan on using it for some other purpose.
I haven't used a miracle blade knife, so can't comment on the mileage of that, but generally speaking, any sort of blade held in the hand will most likely run off, and there's always the risk to the user to consider.
I'm sure there are loads of folk using various types of saws, I have in the past too, but the dust and noise produced when doing lots of boards, especially when I make boards overnight at home, forced me to find a better solution.
rgds