I noticed today that there's some missions that come in as, for example, Residential Fire (Fire Alarm System) or something similar to that. To make the game more realistic, I think that having the mission read "Box alarm" as a separate mission with multiple different variants that can evolve into fires or simply stay as a box alarm.
In other words, mission comes in as a box alarm, requires 1 engine and 1 ladder, and can evolve into a residential fire, drug lab fire, high rise fire, etc.
To me, this makes more sense because most of the time when we are dispatched to a box alarm, its nothing but has the chance to turn into a fire, but you as the player would not know what call would be coming as a result of that.