This poor schlub is the first of many Nazis at the Schloss Adler who probably wishes he hadn't shown up for duty that day.
A curt "Hello?" from Schaffer brings the hapless German out to see who's stopped by... only to get plugged in the stomach from Schaffer's silenced Walther PPK. He pitches over into his chair as Schaffer, just for good measure, shoots him a second time in the back.
Even in death, our pal the phone operator finds no peace, as Schaffer props him upright in his chair at his desk, so that he'll appear to be alive when the pilot comes in later.