“Sinners” steals the show at the SAG Awards, and the biggest moments happen in the room, not just on TV. On Sunday, Viola Davis announced Michael B. Jordan as best male actor and the hall erupted. Minutes later, presenter Samuel L. Jackson yelled with excitement as “Sinners” won best ensemble. Castmates rushed together and the whole room stood and cheered. During the commercial breaks, actors raced to the bar, the bathroom or to friends’ tables. A gospel performance of “This Little Light of Mine” got people dancing.