Si IV lines at λ1393 and λ1402 observed with HST in 1999 and 2000 showing the absorption components formed in material that is approaching the observer at velocities of −684 (1999) and −715 (2002), speeds that correspond to the model presented in this paper. These components are no longer visible in 2002. Also indicated with vertical lines are the interstellar absorption components associated with the Galaxy and the SMC, as well as a line-of-sight supernova remnant. All plotted spectra correspond to orbital phase φ ~0.