  Nice slices have played a pivotal role in the discussion of the black hole
information paradox as they avoid regions of strong spacetime curvature and yet
smoothly cut through the infalling matter and the outgoing Hawking radiation,
thus, justifying the use of low energy field theory. To avoid information loss
it has been argued recently, however, that local effective field theory has to
break down at the horizon. To assess the extent of this breakdown in a UV
complete framework we study string-theoretic effects on nice slices in
Schwarzschild black holes. Our purpose is two-fold. First, we use nice slices
to address various open questions and caveats of arXiv:1402.1486 where it was
argued that boost-enhanced non-adiabatic string-theoretic effects at the
horizon could provide a dynamical mechanism for the firewall. Second, we
identify two non-adiabatic effects on nice slices in Schwarzschild black holes:
pair production of open strings near the horizon enhanced by the presence of
the infinite tower of highly excited string states and a late-time
non-adiabatic effect intrinsic to nice slices.
