Reactionless drive?
Even were it possible, a craft powered by such a device still couldn't travel faster than light. If the author understands e=mc^2 they should realise that only by converting a body completely to energy can it reach the speed of light. As the craft approaches the speed of light time dialation effects become apparent. The acceleration experienced by the occupants remains constant, but to an external observer it reduces. As they approach light speed their time slows to zero as does their acceleration.
The whole hyperspace/wormhole thing in SciFi is a plot device to get around this problem.