The new Hearth & Horizon story, The Door That Opens In, is about a number people rarely put next to another: last year's gate count (910) and the church's fire certificate (450).
The arithmetic the parish assistant does is short. 210 m² of standing floor at about two people per m² is 420. A thousand inside is nearly five per m², where a crowd stops choosing its own movement. Two doors, 1.6 m and 0.9 m, lose about 15 cm at each edge to give 1.9 m of working width. At roughly 1.3 people per second per metre that is about 148 a minute: 420 out in under three minutes, 1,000 in about seven, if nobody stops. The danger is the stop, an inward-opening door and one person who falls.
What the story keeps from the physics is the humility: the certificate, not the sum, is the number; the attendance is a range (700 to 1,300), not a forecast; and a good day does not show the plan would have held on a bad one. The figures are illustrative engineering rules of thumb, not a standard, and the parish is invented. Text only: the audio folder is over its size cap.
Story: ventures/hearth-and-horizon/stories/the-door-that-opens-in.md.