I suspect that the light was flashing green for the through traffic and the driver believed that a left turn was now permitted.  The pedestrian was probably crossing the cross street which typically has a stop sign and a flashing red, and is not obligated to push any kind of button or wait for a signal in order to cross.  A flashing green arrow for a left turn also means that pedestrians are restricted from crossing the street you are about to turn into.  This confusion could easily happen to anyone unfamiliar with BC's flashing green pedestrian controlled lights.  Conversely those of us from BC are likely to get honked at in other jurisdictions where the flashing green means advanced left turns as we sit there waiting for an arrow.