Have you seen the film where 'Shackleton dances' to entertain the crew. That's not what happened.
Shackleton, Worsley, and "motor-expert" Orde-Lees took the motor sledge out for a trial. Out on the ice, far from the ship, the motor broke down. While fixing the motor, Orde-Lees began to whistle "a one-step" The Policeman's Holiday. To keep warm, Shackleton and Worsley began dancing to Orde-Lees apparently impressive whistling.
The Policeman's Holiday - https://www.youtube.com/watch?v=4NIbwmFODzM
Here's Orde-Lees' account of the incident in his expedition journal...
April 30, 1915
Very clear & bright but with a rather cold wind.
We took the motor out again & ran it up & down the frozen lead. (Incidentally doing a bit of hummock climbing.)
It went splendidly & the way it surmounted the hummocks was wonderful. Sir Ernest & Captain Worsley accompanied me & it was as much as they could do to keep up with the motor.
The new lid was not an unqualified success; the water manages to work round & drip on the carburetor & magneto & cause trouble. It did. During the ensuing investigation on my part Sir Ernest & Captain Worsley danced together on the floe - a one step - whilst I sang & whistled, "The Policeman's Holiday." It was most amusing & not a little incongruous to see the great polar explorer thus gyrating on the Antarctic ice.
That is Sir Ernest all over though.