If you set everything on fire, you won't have enough firemen
Firefighters will very seldom have enough people and water to put out a fire immediately. They have to choose (prioritize) where they can effectively douse the flames to first contain the fire - essentially ignoring the rest of the fire - and then work it down until it’s extinguished

In crisis situations everything becomes a fire, or so it seems. Crisis management requires management to put an extra effort in prioritizing tasks and assigning them to the correct resources. The real challenge is that in many cases, the crisis situations stem from the very same management team charged with prioritizing, for not helping set priorities to the point that they started the fires.
When we fail to give our teams priorities, and constantly ask for multiple things “right now” we significantly raise the risk that nothing will get done, or that the task that gets done will be one less critical to the success of the team. As things start to become fires the teams charged with executing get overwhelmed (and pardon the cliché – burned)

Here is the problem; when individuals are given multiple URGENT tasks simultaneously, studies have shown that they will likely complete the easiest ones first. Essentially, as a manager you have inadvertently relinquished all control to your team and their own logic for prioritizing. Unless you have a team of all-star performers, it is likely that tasks will not get done in optimum order, and in a worse case you may end up with many half-started tasks that never get completed.

The manager’s job is to point the limited water cannons to the area where they can have the greatest impact.

My method to prioritize, and how I’ve witnessed many successful managers prioritize successfully, is by setting a daily meeting with your team to review tasks and set priorities. By doing this, even when everything is urgent, you set the focus for your team, and you have full control over the execution. As the truly urgent tasks are being completed, you can then delay (or run interference) on the other tasks until your team is ready to take those on.