Webber was stuck behind traffic that were on wet tyres. Button was closing in fast on intermediates, on a drying track, lapping faster even than the leaders. Vettel was leading, but doesn't have enough of a gap to do a pitstop and clear the traffic that Webber was stuck in at the time. What, then, should Red Bull have done?
Yes, in hindsight, there was the rain, and Button, along with those on intermediates, had to pit again. Without the benefit of hindsight, Red Bull would be potentially risking Webber's position if Button passes him with a pit stop in hand.
