I have seen the video of this particular scene a few times. What you don't see in all the photos is that right behind Ullrich is one of the USPS climber, I think it was Jose Luis Rubiera, but it might have been Victor Hugo Pena. It always looked to me as if Lance was looking past Ulrich at his teammate trying to guage whether he was going to be able to respond and maybe come up to pull a little more. Then sometime in the last year or so, Lance even said as much on one of the tour review shows. He acknowledged that he certainly may have glanced at Ullrich but was mainly checking on his teammate's status.