This manuscript constitutes an editorial merge of three complementary texts focusing respectively on the calculation of the Gamow factor for low-energy D–D and p–D reactions, the numerical sensitivity of this calculation to regularization parameters, and a topological coherence methodology applied to critical cyber-physical systems. Rather than juxtaposing these materials, the present document reorganizes them around a common axis: the reliability of critical models, understood as the articulation between theoretical framework, numerical stability, traceability of hypotheses, and verification discipline. The physical core remains the semi-classical evaluation of tunnel transmission under an effective potential combining Coulomb repulsion, electron screening, and a centrifugal term. The sensitivity analysis results show that absolute probabilities vary significantly with certain regularization choices, whereas the amplification ratio due to the screening remains remarkably stable, making it the most robust observable. The topological coherence framework is then mobilized not as a second experimental study on the same physical object, but as a methodological extension designed to strengthen the discussion on verification.