You've got to really watch out that you leave enough time for the trek back to the station, with a little margin built in. Unlike the way I did it, you need to start your goodbyes a bit earlier. The other tip is, assuming you'll be eating at the same place or in the same part of town, is to try and aim for the middle cross underpassage of the station rather than heading all the way down to the front of the station. This is a passage that crosses under about halfway up the platforms and leads over to Sihlquai.

Unfortunately there is no way I'll make the 22nd April because I have to conduct a performance of Chitty Chitty Bang Bang in Geneva that night.