Find corresponding worker based on shift begining and end datetimes

I would keep the tables disconnected, or - if you must - create a Stations dimensional table.

Regardless, the calculated column in the Events table would just reference the  entire workers_shifts table with the appropriate filters

Meta Code:

Emp = 
var s = selectedvalue([Station ID])

var d = selectedvalue([Timestamp])

Return calculate(max(workers[Worker ID]),workers[Station ID]=s,workers[Shift start]<=d,workers[Shift end]>=d)