A call for volunteers is raised. The crowd murmurs and shuffles uncertainly, there are a lot of sideways glances, but no-one moves forward. After a tense few seconds, however, one person raises their hand. Cue a musical crescendo as more people join in - and ultimately everyone has volunteered... or, at least everyone important to the story.
This is a sister trope of Slow Clap
. Perhaps both could be fit under a "One Starts The Trend
" umbrella, encompassing applause, volunteering, singing (in silence one person starts to sing and everyone joins in), cheering, etc..? Suggestions welcome.