In this paper, the authors investigate the non-perturbative bulk Hilbert space of 2D Jackiw-Teitelboim (JT) gravity, both with and without matter. They provide an explicit definition of a non-perturbative Hilbert space in terms of metric variables, which is highly degenerate and includes null states. The states are wavefunctions of the length and matter state, with a non-trivial inner product. The authors identify null states and discuss their importance for defining operators non-perturbatively. They study two bulk linear operators that may serve as proxies for the experience of an observer falling into a two-sided black hole: one captures the length of an Einstein-Rosen bridge and the other captures the center-of-mass collision energy between two particles falling from opposite sides. They track the behavior of these operators up to times of order $ e^{S_{BH}} $, at which point the wavefunction spreads to the complete set of eigenstates of these operators. If these observables are indeed good proxies for the experience of an infalling observer, the results indicate an $ O(1) $ probability of detecting a firewall at late times that is self-averaging and universal. The paper also discusses the non-perturbative geodesic Hilbert space, the definition of non-perturbative bulk operators, and the implications for the bulk Hilbert space and associated observables in any theory of quantum gravity. The authors highlight the importance of the non-perturbative inner product and the role of null states in defining operators non-perturbatively. They also discuss the implications of their results for the firewall problem and the non-perturbative Wheeler-DeWitt equation.In this paper, the authors investigate the non-perturbative bulk Hilbert space of 2D Jackiw-Teitelboim (JT) gravity, both with and without matter. They provide an explicit definition of a non-perturbative Hilbert space in terms of metric variables, which is highly degenerate and includes null states. The states are wavefunctions of the length and matter state, with a non-trivial inner product. The authors identify null states and discuss their importance for defining operators non-perturbatively. They study two bulk linear operators that may serve as proxies for the experience of an observer falling into a two-sided black hole: one captures the length of an Einstein-Rosen bridge and the other captures the center-of-mass collision energy between two particles falling from opposite sides. They track the behavior of these operators up to times of order $ e^{S_{BH}} $, at which point the wavefunction spreads to the complete set of eigenstates of these operators. If these observables are indeed good proxies for the experience of an infalling observer, the results indicate an $ O(1) $ probability of detecting a firewall at late times that is self-averaging and universal. The paper also discusses the non-perturbative geodesic Hilbert space, the definition of non-perturbative bulk operators, and the implications for the bulk Hilbert space and associated observables in any theory of quantum gravity. The authors highlight the importance of the non-perturbative inner product and the role of null states in defining operators non-perturbatively. They also discuss the implications of their results for the firewall problem and the non-perturbative Wheeler-DeWitt equation.