6 on the court

[Blindolbat]

Question for the group.
We had a disagreement at our Association meeting last night and I would like the group's input. Essentially, is there a definition for participating?

10.1.6 says, "A team shall not:
Have more than five team players participating simultaneously."

Situation: Team B breaks timeout huddle and plays with 6 but officials do not notice and then the ball goes out of bounds. Officials now notice 6 players on the floor. Can player for team B leave the floor without penalty because he/she is not currently participating during a dead ball? Or, because no player has come on the court during the dead ball, can we assume there were 6 players during the last live ball and thus assess a technical foul?