Coach leaves box

[All_Heart]

Rule 10-5-2 The head coach may also confer with personnel at scorer's table to request a 60-second time-out (or one 30-second time-out if that is the only type of time-out remaining) for a correctable error as in 2-10, or to prevent or rectify a timing or scoring mistake or alternating possession mistake.

Is this the only time a coach may leave the coaching box during a live ball? What if the coach has to use the bathroom or something else comes up? Is this covered using 2-3?

This question was raised because someone was watching a JV game and the coach disappeared for half the quarter.