Emission line properties during obs-2. Left panels: velocity offset of Si XIV (top-left). The coloured horizontal bands mark the results for obs-2.A, obs-2.B and obs-2.C (with their velocity width representing ±1σ errors). The colour code is the same as in Fig. 1. The evolution of the FWHM is presented in the bottom-left panel, where the horizontal dashed lines indicate the FWHM of Hα during GTC-2. The Si XIV measurement obtained during GTC-2 (i.e. top-right) is indicated by a star. Right panels: emission line profiles (in velocity scale) of Mg XII, Si XIV, S XVI (top-right); Hα and He I (bottom-right) during GTC-2. For an easier visual comparison, the velocity resolution of the optical lines has been degraded to that of Chandra. The vertical lines are the same as in Fig. 2.