Dan O posted an excellent map of the TSBD 1st floor........
There appears to be a door at the NW corner of the 1st floor that goes from the 1st floor stairway landing out to the loading dock. I wonder why Adams and Styles wouldn't have exited the building through that door?
The map shows exactly the distance that Adams and Styles needed to cover from the stairs of the loading platform, around the loading platform in the direction of the railway yard, around the annex warehouse building and down the street in front of the TSBD to the main entrance.
When the women arrived at the main entrance, Styles went straight back into the building without being stopped by police. In other words, before the building was locked down at 12:36 or 12:37.
If the women arrived at the front entrance at 12:36 or 12:37, considering the distance they covered as well as the time needed to go down the stairs, what do you think was the latest time for them to leave the 4th floor?