When Gideon made his way to the mall, he had taken off his coat, but not trusting his coworkers enough to leave his wallet in the pocket, had taken it out and instead slipped it into the left pocket of his trousers.
When the card began vibrating, Gideon didn't feel the vibrations coming from it, and it took him a while before he heard the buzzing noise produced by it. When he did notice it, Gideon stopped his cleaning of the floor on the ground floor of the mall, and looked around with a sligtly puzzled expression on his face, not imediately realizing where the buzzing noise came from. When he did realize, he reached for his wallet with a more puzzled expression, and opened it, seeing the card glow. So that's what's up. He looked at the card for a little longer, before finding one of hos co-workers and asking them what colour the card was glowing. Being told it was green, Gideon thanked the coworker, closed the wallet again, and slipped it back in his pocket. Knowing green meant that the call wasn't urgent, Gideon continued his work.