The top panels show the flux maps of the three [O iii] detections, clump-I, -II, and -III (from left to right). Black contours show emission at levels of 2, 3, 4 and 5σ. The location of the BDF-3299 galaxy is marked as a black cross (in the third panel the mark is outside of the field of view). The bottom panels show the spectra of the line emitters at a spectral resolution of 10 km s^-1. The yellow shaded region shows the region used to integrate the flux to obtain the maps in the upper panels. Velocities are relative to the Lyα peak of BDF-3299. The red dotted spectrum in the left panel show the [CII] spectrum shown in Fig. 2 and scaled arbitrarily up in flux density for comparison.