The combat was well written! The story doesn't really feel like it fits into the "impossible" theming though. The lone Custodian soldier comes up with a very simple plan and executes it flawlessly while slaughtering a number of Sisters units, which again is very nicely written but does seem more like an impossibility for the Sisters rather than the Custodian. His undoing honestly feels out of character you presented in the first part, and leaves me wondering "why would he do that?"