Maybe more like the drive that Solomon Epstein started with in the novella, The Drive, but with fission instead of fusion. I don't think it would be any good for a manned ice-hauler trip out passed the belt though as that would face the same problems that a trip to Mars currently faces.
On the other hand, if such a drive could get a crewed ship to Mars in two months then it should be able to reach the outer planets in a reasonable time with a much larger payload than we can manage now. We might well be able to send large robotic probes to the moons of Saturn and Jupiter like the ones we've sent to Mars and get there in months instead of years.
Yes, what we call the speed of light is really the speed of light in a vacuum. When light passes through a medium like water or glass it travels slower. That causes the light to be refracted which means that it changes direction slightly based on the energy of the light (color) and the refractory index the material. Glass will refract a red laser by a certain amount while water will refract it by a different amount.
Fun fact, because different colors refract differently, when you shine a white light through a specially shaped piece of glass called a prism, you will see a rainbow pattern.
https://www.science-sparks.com/wp-content/uploads/2019/06/shutterstock_1194072568-1024x606.jpg.webp
"The most pressing problem is not that they’re [AI] going to take our jobs, not that they’re going to change warfare, but that they’re going to destroy human trust. They’re going to move us into a world where you can’t tell truth from falsehood. You don’t know who to trust. Trust turns out to be one of the most important features of civilization, and we are now at great risk of destroying the links of trust that have made civilization possible." - Daniel C. Dennett
In a few years you will not know what is true or false unless you see it in person with your own eyes. Even video and audio proof are going by the wayside.