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.