Lyα-pumped iron emission in GLIMPSE-17775. Left: observed Fe II flux ratios (black points), normalized to Fe IIλ9075, compared with predictions from Lyα fluorescence models of T. A. A. Sigut & A. K. Pradhan (2003, blue). The close correspondence across ∼14 lines indicates a common excitation mechanism driven by Lyα pumping in dense, partially shielded gas. Right: zoom in on the λλ9000–9400 complex, showing the remarkable agreement between the modeled continuum-subtracted Fe II spectrum (black) and the T. A. A. Sigut & A. K. Pradhan (2003) model (blue). We show air wavelengths of each Fe II line directly from T. A. A. Sigut & A. K. Pradhan (2003), including the blended features. Together, these comparisons support an origin in the dense inner regions of the cocoon surrounding the accreting black hole.