Continuum-subtracted, defringed spectra with peak S/N ≳ 10 extracted from Regions 1–3 (Figure 1). Lines are fit by up to three Gaussians with different Doppler-shifted v_rad (dashed gray lines), corresponding to the Bar (v_Bar ∼ 0 km s⁻¹), Northern Arm (v_NArm ∼ −270 km s⁻¹), and BC structures (v_BC ∼ −570 km s⁻¹). All lines are colored by IP and expressed in relative flux density units, normalized to the Bar’s peak flux. Top: α elements. Bottom: [Fe III] 22.93 μm and [Ni III] 7.352 μm. See Appendix B.1 for further discussion of rest wavelength uncertainties for these lines. Dashed gray lines indicate each fit component’s v_rad averaged across lines and 1σ standard deviation. The saturated portion of Region 3’s [Ne II] 12.81 μm line is marked with a blue shaded box. The Northern Arm and BC structures have relatively stronger higher-IP lines than lower-IP lines when compared to the Bar. They also show strongly enhanced nickel flux relative to iron when compared to the Bar.