Indeed if it was a BK117 then the tail rotor is usually too high to be contacted by any but a very tall person.
According to a German EMS forum it was D-HDDD, a DRF BK-117 acting as "Christoph 51", an intensive care helicopter based in Stuttgart. With the tail rotor on that one being as high as it is it either takes a very tall person as you say - or a deliberate action. I wouldn't be surprised
