Anyone who has operated in Europe will know that it is very common. They have radars which give predicted velocity and departure times. And also 3D radars. Manytimes you will find that an aircraft is given permission for take off when the landing aircraft has not even cleared the runway. The predictive radars tell the ATC officer where an aircraft can clear of the runway and they order the pilot to clear off on the particular runway exit link. Pretty common. nothing to be foxed about.