There is a massive difference between playing in an ensemble, wether it is an orchestra or a rock band, and performing a solo piece in front of a live audience.
The soloist has no safety net whatsoever. There is only him or her and the audience. It is one of the purest forms of communication. Whatever that soloist is thinking, it travels directly through the instrument and into the audience’s ears. No filters. No editors, or managers, or artifice of any kind.