We present simulation evidence from the Black Hole Hunter (BHH) acoustic analog simulator(PDRI_PDDU_v3.4 — Pax-Dualon Diagnostic Universum) for a previously undescribed blackhole growth mechanism: internal field-dynamic breathing cycles producing measurable netradius gain independent of external accretion. This mechanism does not replace accretion butrather underlies it, providing the fundamental duty cycle that accretion modulates in amplitude.Across multiple simulation runs and parameter sets, the simulator spontaneously producescyclical radius oscillations between an expanded swelling phase and a contracted collapsephase. The simulator's automated spherical core detection reports explicit radius values at eachphase transition, documenting a collapse minimum of r≈2.50 and a peak swelling radius ofr≈8.89 within a single run, with net radius growth continuing post-collapse. Two reproduciblevisual field signatures distinguish the phases: loose vertical banding during swelling and tightpolar banding with inter-polar triangular patterns during collapse. These signatures areparameter-independent across V0_IN and SCALE values. Cross-correlation analysis of theinner and outer horizon spectral entropy (H_in, H_out) reveals a measurable acoustic lagbetween horizons that scales directly with the SCALE parameter — providing a physicalmechanism linking black hole mass to AGN duty cycle timescale. The addition of a dark matterhalo component stabilizes and regularizes the breathing cycle, consistent with the observedcorrelation between host halo mass and AGN variability. We connect these findings to theepisodic radio galaxy J1007+3540 (Kumari et al., 2026), whose layered jet structure documentsat least two complete breathing cycles and whose cluster environment directly mirrors the halostabilization effect observed in v3.4. Five testable observational predictions are derived. Kumari et al. (2026) reported detailed observations of J1007+3540, a giant episodic radiogalaxy whose jet structure documents multiple distinct episodes of AGN activity separated byperiods of dormancy. The layered morphology reveals older outer lobes approximately 240million years old overlaid with younger, brighter inner jets approximately 140 million years old —representing at least two complete activity cycles with an intervening dormancy period ofapproximately 100 million years. The galaxy resides within the WHL 100706.4+354041 cluster,characterized by hot intracluster gas, high pressure, and strong drag forces acting on the radiojets. Remarkably, despite being hosted by a massive elliptical galaxy with stars formed 12 billionyears ago, J1007+3540 continues producing new stars at over 100 solar masses per year — astar formation rate consistent with repeated collapse-driven energy injection into thesurrounding gas, as predicted by the breathing cycle framework presented here.The standard accretion model offers no satisfying mechanism for such episodic reactivation.Accretion disk reservoirs do not persist across 10⁸-year gaps, and external triggering eventscannot account for the apparent regularity of AGN duty cycles observed across the episodicradio galaxy population. The central question J1007+3540 poses is not merely why this blackhole reactivated, but why it does so repeatedly, on a timescale that appears set by an internalclock rather than by the stochastic availability of external fuel. As we show in Section 2.3, thistimescale is naturally set by the acoustic travel time across the sonic horizon — a quantity thatscales directly with black hole mass.We propose that this internal clock is the acoustic breathing cycle of the black hole itself. TheBlack Hole Hunter (BHH) acoustic analog simulator, developed at the Pax-Dualon ResearchInstitute, models the interior of a black hole analog using coupled scalar fields on a sphericalsurface, grounded in Unruh's (1981) sonic hole analogy. In Part 1 of this series, we documentedsix pre-observation predictions about OJ 287 confirmed by JWST, Chandra, and Event HorizonTelescope observations, including a Kerr spin parameter match to our independently derivedvacuum resonance frequency ω₀ = 0.313 Hz [McKenna, 2025].Here we report a new emergent behavior discovered in extended simulation runs: spontaneouscyclical breathing cycles in which the measured spherical core radius oscillates betweenexpanded and contracted states with a net positive radius gain per cycle. Cross-correlationanalysis of inner and outer horizon spectral entropy reveals that the acoustic lag betweenhorizons — and therefore the breathing cycle period — scales directly with the SCALEparameter controlling horizon size. This provides a physical mechanism connecting black holemass to AGN duty cycle timescale, offering a natural explanation for J1007+3540's 100-million-year dormancy periods without invoking external triggers.