My idea for a new large scale event, once new vehicles have been added.
Riots. Like we seem to see more often now a days.
Calls such as looting, building fires, large scale crowds, injured people, damage.
Would require all three services with vehicles such as Public Order Vans, ARV, Prisoner Transport buses.
Second Event
Terrorist Attacks same as above but could choose from explosive, shooting and chemical.
All would require the different types of units.