Two kinds of garage door calls cannot wait. The door stuck open with the house exposed overnight, and the door stuck shut with the car inside and work in the morning. Both get triaged ahead of everything else on the board, and the pros here treat them that way.
What counts as an emergency
Door stuck open, especially at night; a garage full of tools, bikes, and a door into the house is not something to leave exposed
Car trapped inside, the spring broke with the door down and the opener cannot lift dead weight
Door hanging crooked or off its tracks, a door that could drop is a hazard to anyone near it
Cable snapped with the door up, the door is supported by a thread and gravity
Before you do anything else
Stop running the opener. Every press of the button on a door with a broken spring or cable makes the motor fight the door's full weight, and a few tries can turn a spring job into a spring plus motor job. If the door is stuck open, unplug the opener if it is straining, clear kids and pets away from the opening, and wait for the tech.
The manual release, carefully
The red emergency release handle disconnects the door from the opener. On a healthy door that lets you lift it by hand. On a door with a broken spring it leaves you holding a very heavy door, and on a door with a snapped cable it can mean the door drops. Use it only if the door moves smoothly by hand first.
What an emergency visit covers
Get the door secure and working if the parts are on the truck, which for springs and cables they usually are. If the fix needs an ordered part, the goal of the call is a door that closes and locks tonight with a scheduled return for the permanent repair, not an open garage and a promise.
