  We investigate in the context of brane inflation the possibility of
additional light scalar fields generating significant power spectrum and
non-Gaussianities at the end of inflation affecting the CMB scale observations.
We consider the specific mechanism outlined by Lyth and describe the necessary
criteria for it to be potentially important in a warped throat. We also discuss
different mechanisms for uplifting the vacuum energy which can lead to
different dominant contributions of the inflaton potential near the end of
inflation. We then apply such criteria to one of the most detailed brane
inflation models to date, and show that inflation can persist towards the tip
of the throat, however for the specific stable inflationary trajectory, the
light residual isometry direction becomes degenerate. We also estimate the
effects for other inflationary trajectories with non-degenerate residual
isometries.
