To Meet On Silent Footfalls

This is before Shinichi's time as a renown detective: a time where Shinichi wasn't such a good detective yet and didn't know everything. One night, during a retrieval and arrest operation of the police, he meets somebody... This has emerged due to a Writing Challenge on the poirotcafeproboards forum! Thanks for the idea! The topic? A late-night heist, and two old rivals meeting...