User blog comment:Mobo85/Hot off the Presses: "Across the Second Dimension" Debuts August 5/@comment-3212462-20110607100630/@comment-181516-20110610092749

If you think about it, Candace knows that Phineas and Ferb can take care of themselves and I'm sure by that point of the movie she finds out about Perry's secret judging by her expression when they were fighting robots in that train.