A fast-moving weather pattern is crossing through the skies. Can we complete an overground game - based on station doorways - before we have to take avoiding action? [Avoiding action means either manning the lifeboats, buying one of those cheap umbrellas that last for one shower before being dumped upside-down in lamppost-mounted litter bins like crucified cormorants, or diving for cover in an underground station and being forced to change lines.] Usual winning move.

And so it begins...

This is the end of the line. There is no more.