As I gathered from what rthus said at the time was that, yes he was in a Pz and camping a spawn at A1 but, 50% of these were one person. Apparently the 'target' in question would appear near him, vanish again and he would get a prox kill.
Quite something watching this rack up. At some points the kills were very rapid and he would get a string of three or so in as many seconds.
We were all cheering him on.