Image and spectra of 4270. (a) 3-arcsec false-colour cutout. The nominal location of the shutters is overlaid; the MSA acquisition accuracy is better than one NIRCam pixel (0.03 arcsec); the grey circle represents the FWHM NIRSpec PSF from webbpsf at the observed wavelength of [O III]λ5007. (b) 2D spectrum of 4270 at z = 4.023. The y axis has been shifted so that the centre of the galaxy is at pixel 0. The physical scale of one pixel is reported on the plot (0.1 arcsec/pixel). (c) 1D spectrum of 4270. We note the complex morphology of this galaxy: the synergy between spectroscopy and imaging is vital for correctly interpreting spatially resolved slit spectroscopy. The simultaneous presence of high-ionisation and low-ionisation species, including auroral lines (cf. He IIλ4686 vs. [N II]λ5755, [O I]λλ6300, 6363, [O II]λλ7319 − 7332, and possibly [N I]λλ5198, 5200), may indicate a complex interplay between AGN photoionisation and shocks.