You can use Daily add additional jobs to an existing route, even when the crew member is already in the field. This technique is a little more manual than BestFit, but can be used to quickly add emergencies to today's route.
Beeline routes stops showing jobs on the route once they've been started. So whenever you're viewing today's routes, you're viewing jobs that the tech hasn't started yet.
Just make sure you click "Confirm Routes" after you create the new job so the remaining jobs in the route get their updated arrival times.