The Price of One Event: The Flux Tension Between the KM3NeT Ultra-High-Energy Neutrino KM3-230213A and IceCube, with Each Resolution Costed

On 13 February 2023 KM3NeT/ARCA recorded KM3-230213A, a muon implying a neutrino of median energy 220 PeV, the most energetic ever observed, while IceCube's 12.6-year extremely-high-energy search saw no comparable event. This paper computes, from published exposures and effective areas, the diffuse E^2 flux the single event implies (5.8e-8 GeV cm^-2 s^-1 sr^-1 per flavour), the ~70 events IceCube would expect at that flux, and the correctly conditioned tension: p = 0.014 (which-detector test) and p = 0.0035 (saturated likelihood-ratio test), consistent with the published joint fit p = 0.004. For a transient point source the implied fluence is 8.8e-2 erg cm^-2 (single-detector) or 5.5e-3 erg cm^-2 (joint), with a residual tension of about 2.1 sigma. Each resolution is priced: a cosmogenic origin needs a flux boost of x160-1750 over benchmark models, requiring source evolution far beyond the star-formation rate to z ~ 6; a transient needs duration <~2 yr, a hard spectrum, and an all-sky rate <~0.4 per year; a statistical fluke costs one chance in 78 under the joint flux. All numbers come from the deposited Python script.