This one actually got its inspiration from a Cracked article about games you should give a shot playing in your own head to make life more interesting. One of these was to have a look at people on the street or train platform or bus and figure out which one of them was a spy or assassin and who their target was.
She stepped down onto the platform and took up her place next to the air conditioning vent, to the right of the small conductors' office. Her mark was already standing there, as was her second sent by the Agency.
She threw a casual glance at the two of them. After a day or so of not being up close to him, the mark was much fatter than she remembered. And the agent was a short, handsome man with small glasses. Like they had organized, he was reading that free gossip newspaper they hand out at train stations.
The rumble from underneath the platform told her that the train was almost here. She put her bag down onto the air conditioning vent and dug around and found her black day planner. She opened it and began writing. Hopefully the Agent would notice. This was the signal that everything was a go. A chattering group of school children passed her and she watched them go. Made eyes with the Agent. She turned away. On the bench, the Agent put the newspaper into his satchel bag and took out a small black book of his own and had a look at something, nodded, and replaced it in his bag.
The train pulled up to the station. The Mark checked his watch. It was late. The doors opened and the Mark went on. She followed and right behind her, the Agent stepped onto the crowded train.