my.coxph = function(x, t, e)
# Simple CoxPH with silenced errors.
{
  m = try(coxph(Surv(t,e)~x, data=data.frame(t=t,e=e,x=x)), silent=TRUE) 
  p = NA
  if (!inherits(m, 'try-error')) {
    s = summary(m);
    p = s$coefficients['x', 5]
  }
  return (p)
}


# options(mc.cores=4)

pv =
mclapply(as.data.frame(X),  # the columns will become entries in a list
  my.coxph, C$t.rfs, C$e.rfs,
  mc.cores=4)