Stein wanted to go to Karakura town.
He thought about going.
He decided he would go.
He thought he was already in Karakura town.
He must have misread or misheard or maybe dreamed something somewhere along the line.
He was very confused about all of these rules and stigmata.
He wanted to go to that town very badly.
So he smoked a ciggerate and walked into the Senkaimon gate and into the Dangai.
There he ran from a giant train known as the Janitor or in english dubs the cleaner.
He eventually got to the end of the tunnel.
Just like a dead guy going to heaven he emerged from the light.
He was finally where he thought he should be.
That was Karakura town.