[Varyon]

Missiles have a few ways they can out-accelerate ships. First off, they don’t have squishy crew, so can actually have higher acceleration. Next up, while not RAW, I feel it should be possible to design vessels that dedicate more than 3/10ths of their mass to acceleration - a missile that has (say) a reaction drive that takes up 15 systems is going to outperform any manned ship, at least while the missile has reaction mass left. Finally, and also not RAW, is the suggestion of single-use reaction drives having better performance than the default reusable systems. A related option, from I think SS7, is to forgo the radiation shielding on a nuclear or antimatter drive system. This makes the vessel rather unsafe for passengers and reduces its HT, but IIRC doubles the acceleration (because you use the mass savings from leaving out the shielding to make the drive bigger).