It should have been easy.
Calculate all the variables, all the things that could go wrong during their daring escape. Calculate when the guards would be patrolling that area of the museum. Calculate how many minutes it would take for them to disarm the security system for the modern arts wing, how long it would take to lift the protective covering, also with its own added security, and then lift the painting before anyone got suspicious.
It should have been easy to calculate all that. From the time the heist began to the time she would be staring at the priceless painting in her secret lair should have been under 45 minutes.
But then, as she was playing the distraction, in case anyone did come around asking questions, she ran into him.
There was no way she could have calculated how the slope of his jaw could have ruined their entire plan, nor how his need to help her find the ancient Egypt exibit (the farthest from the modern art wing) would have saved the plan as the words bumbled their way out of her mouth.
Yes, the painting looked nice next to all of her other stolen artifacts, but if she had calculated a little better, she might have reached the answer to the entire equation.
His phone number.