Out-of-equilibrium, strong correlation in a many-body system can trigger emergent properties that act in important ways to constrain the natural dissipation of energy and matter. Networks of atoms, intricately engineered to arrange positions and tune interaction energies, exhibit striking dynamics. But, strong correlation itself can also act to restrict available phase space. Relaxation confined by strong correlation gives rise to scale invariance and density distributions characteristic of self-organized criticality. For some time, we have observed signs of self-organization in the avalanche, bifurcation and quench of a state-selected Rydberg gas of nitric oxide to form an ultracold, strongly correlated ultracold plasma. The robust arrested relaxation of this system forms a disordered state with quantum-mechanical properties that appear to support a coherent destruction of transport. Work reported here focuses on initial stages of avalanche and quench, using the mm-wave spectroscopy of an embedded quantum probe to characterize the intermolecular interaction dynamics associated with the evolution to plasma. Double-resonance excitation prepares a Rydberg gas of nitric oxide composed of a single selected state, n0f (2) (referring to a particular principal quantum number from n0 = 30 to 70 in the f ( = 3) Rydberg series converging to the NO + rotational state, N + = 2). Penning ionization, followed by an avalanche of electron-Rydberg collisions, forms a plasma of NO + ions and weakly bound electrons, in which a residual population of n0 Rydberg molecules evolves to high-. Predissociation depletes the plasma of low-molecules. Relaxation ceases and n0 (2) molecules with ≥ 4 persist for very long times, evidently under collision-free conditions. At short times, excitation spectra of mm-wave Rydberg-Rydberg transitions, n0f (2) → (n0 ± 1)g(2) mark the rate of electron-collisional -mixing. At long times, n0 (2) → (n0 ± 1)d( 2) depletion resonances signal collision-free energy redistribution in the basis of central-field Rydberg states. The widths and asymmetries of Fano lineshapes witness the degree to which coupling to the arrested bath broadens the bright state as well as how bright-state predissociation mixes the network of levels in the localized ensemble.