Look at this play another way suppose K possesses the ball at the R30 and starts running towards R's end zone. We would blow the play dead as soon as K possessed the ball and R would put the ball in play where K possessed the ball or the spot of 1st touching, whichever would be more advantageous for R.
Scenario described the ball, becomes dead when K possesses the ball at the one yard line. They can carry a dead ball into the end zone, but the ball is just that it's dead and so no touchback