  We investigate graviton radiation in gravitational scattering at small impact
parameters $b<R\equiv 2G\sqrt{s}$ and extreme energies $s\gg M_P^2$, a regime
in which classical collapse is thought to occur, and thus radiation may be
suppressed also. Here however, by analyzing the soft-based representation of
radiation recently proposed in the semiclassical ACV framework, we argue that
gravitons can be efficiently produced in the untrapped region
$|\boldsymbol{x}|\gtrsim R>b$, so as to suggest a possible completion of the
unitarity sum. In fact, such energy radiation at large distances turns out to
compensate and to gradually reduce to nothing the amount of energy $E'$ being
trapped at small-$b$'s, by thus avoiding the quantum tunneling suppression of
the elastic scattering and suggesting a unitary evolution. We finally look at
the coherent radiation sample so obtained and we find that, by energy
conservation, it develops an exponential frequency damping corresponding to a
"quasi-temperature" of order $\hbar/R$, which is naturally related to a Hawking
radiation and is suggestive of a black-hole signal at quantum level.
