  We analyze the fate of excitations in regions of closed string tachyon
condensate, a question crucial for understanding unitarity in a class of black
holes in string theory. First we introduce a simple new example of {\it
quasilocal} tachyon condensation in a globally stable AdS/CFT background, and
review tachyons' appearance in black hole physics. Then we calculate forces on
particles and fields in a tachyon phase using a field theoretic model with
spatially localized exponentially growing time dependent masses. This model
reveals two features, both supporting unitary evolution in the bulk of
spacetime. First, the growing energy of fields sourced by sets of (real and
virtual) particles in the tachyon phase yields outward forces on them, leaving
behind only combinations which do not source any fields. Secondly, requiring
the consistency of perturbative string theory imposes cancellation of a BRST
anomaly, which also yields a restricted set of states. Each of these effects
supports the notion of a black hole final state arising from string-theoretic
dynamics replacing the black hole singularity.
