In which case Langston fields sound equally shaky, you've got to bleed off a hell of alot of KE to bleed off. If you want to use it go ahead, but don't say you can explain it. Or accept your going soft sci-fi. There's nothing wrong with that route.
The particles of the slugs have the KE, you can't seperate the two, the energy doesn't just float around after you vaporise the slug. You slow it down, wonderfull, that takes energy, you through in several very fast slugs at the same time and you can't produce enough power to slow them all down.
Behaviour of a fractional c body, well as I can walk at a fraction of c there's your answer.
Seriously though random atmospheric particles and cosmic rays travel at ridiculously high fractions of c, where Einstinean physics, not Newtonian, apply. Hence I've only suggested 0.1c, above that it's stops being 0.5mv2 and gets more complex.
The table merging is from the depths of quantum mechanics, which is a horrendous field I try and avoid. Consider quantum tunneling: You are trapped behind a barrier, say a prison wall. You could exist either side of that wall, but you lack the energy to get through the wall. However quantum tunneling says there is a chance you could just appear the other side of the barrier.
Of course that is epically unlikely, but possible. You can demonstrate quantum tunneling, (particles not people
) and so test assumptions and constants. It's proveable, demonstratable and repeatable. And mind bendingly complex.