Chris Horner is a hoot. Usually he was so strong on climbs he could probably afford to bury himself on behalf of the team leader, stop for a few minutes to guzzle and gnaw some sugar, climb back on the bike and still make the cut. Heck, if they've done enough intervals in training, they've conditioned their bodies for this abuse.
If you watch movies of ye olden dayes of the grand tour, it wasn't unusual for the domestiques to stop and raid cafes along the route to stuff as much as they could carry, hustle back to the front to replenish the team leaders, then drop back exhausted and soft pedal just in time to make the cut and do it all again the next day. But that was before restrictions on feed zones, etc.