Mentoring and consecutive

The world of booths being a mystery, may I assume that mentoring (or is it shadowing?) is part of the process of learning from veterans? I want to assume it is a duo or team work, the human configuration of which allows for mentoring in action. But what about consecutive?

Some agencies suggest that two consecutive interpreters are required when some amount of hours is crossed over. But being alone in the arena has always been standard. No direct customer I know of would ever think about paying for two interpreters.

How and why mentoring could happen in this domain of professional lone wolves? I leave the why for another time, but I have approached a student of mine with a possible invitation to trail me for a day or half a day sometimes next year, and granted the client will agree, to see business interpretation in action, with all its splendors and, at times, mishaps.