He jokes in his Twitter video about knocking on the door but decides that it would inappropriate, and while that might technically be true, I have a feeling this person would not have had a problem with opening their hotel room door to find Hugh Jackman telling them he likes their taste in music.
Clearly, this person is enjoying their music, as Jackman must be hearing the song through a pair of doors.
It appears that Hugh Jackman is walking down a stairwell in a hotel or apartment building when he hears the song “A Million Dreams” coming from the door to the floor as he passes it.
The Greatest Showman | "A Million Dreams” Full Scene with Hugh Jackman | 20th Century FOX