A daily commuter always returned home on the same train, arriving the station at exactly 5pm. His neighbor always arrived the station at 5pm to pick him up.

One day he had an offsite that finished early so he got on an earlier train, that arrived to the station at 4pm. His phone was dead, so he started walking on the route that his neighbor takes to meet him somewhere along the way.
They met and arrived home 10min before the usual time.

Assuming physical car and driving conditions (i.e., the same operation takes the same time). How long did the commuter walk?