  We investigate the simple model of Pennington, Shenker, Stanford and Yang for
modeling the density matrix of Hawking radiation, but further include dynamics
for EOW branes behind the horizon. This allows interactions that scatter one
interior state to another, and also allows EOW loops. At strong coupling, we
find that EOW states are no longer random; the ensemble has collapsed, and
coupling constants encode the microscopic matrix elements of Hawking radiation.
This suggests strong interior dynamics are important for understanding
evaporating black holes, without any ensemble average. In this concrete model
the density matrix of the radiation deviates from the thermal state, small
off-diagonal fluctuations encode equivalences between naively orthogonal
states, and bound the entropy from above. For almost evaporated black holes the
off-diagonal terms become as large as the diagonal ones, eventually giving a
pure state. We also find the unique analytic formula for all Renyi entropies.
