Without commenting too much on this particular accident I cant say I am very surprised that it happened in Istanbul. The taxiways and aprons there are in theory controlled by ATC but the number of ground movements seems to have expanded way beyond their ability to manage with the apparent resources. Add in the blue and orange lines on the taxiways and the additional parking slots that have been constructed and it gets quite chaotic. Its also a place where vehicles seem to run amok and at speed around the aprons.