  We present low-temperature transport measurements of a gate-tunable thin film
topological insulator system that features high mobility and low carrier
density. Upon gate tuning to a regime around the charge neutrality point, we
infer an absence of strong localization even at conductivities well below
$e^2/h$, where two dimensional electron systems should conventionally scale to
an insulating state. Oddly, in this regime the localization coherence peak
lacks conventional temperature broadening, though its tails do change
dramatically with temperature. Using a model with electron-impurity scattering,
we extract values for the disorder potential and the hybridization of the top
and bottom surface states.
