Stephen Tyler Bieneman has pleaded not guilty to misdemeanor assault over the incident last November at McMurdo Station.

A man accused of physically assaulting a woman at a U.S. research station in Antarctica was then sent to a remote icefield where he was tasked with protecting the safety of a professor and three young graduate students, and he remained there for a full week after a warrant for his arrest was issued, documents obtained by The Associated Press show.

Stephen Tyler Bieneman has pleaded not guilty to misdemeanor assault over the incident last November at McMurdo Station, which his lawyer said was nothing more than “horseplay.” The case is due to go to trial Monday in Honolulu.