There are multiple tasks that need to be done and not enough time to accomplish them, unless you have an assortment of friends and a plan to rendezvous long before the place blows sky high. I hope?
You can guess where this trope stems from ...
"Let's Split Up!" - When a group separates, by choice or not, which often results in dividing the narrative, usually to accomplish a task or to create "separation anxiety" for them and for the audience.
This trope can be used in a variety of ways. The most common is used to cover more ground when characters search for something.
Another method is to divide the group when an enemy is after them, forcing the baddie to chase one or the other, just to throw them off or (if more than one baddie) weaken their numbers for an ambush.
Maybe some members in the group can't settle their differences and think it's best to part ways before they bash each other's heads in.
Sometimes, out of their control, the group is forced to split up, either because a tunnel collapses or a bridge gives, or the continents divide!
Ah, man ...!
One of the most effective examples comes from The Lord of the Rings, the original fellowship parting in three ways by the end of the first book. It allowed readers to see more of Middle Earth as the narrative jumped between the three divides of the main group.
"Let's Split Up!" is a fun trope and often works when characters don't want to be separated or if the split otherwise makes sense.
"A mad slasher's after us ... let's split up!" ... I think not.
Have your characters always stayed together, or did they split up? What are your favorite "Let's Split Up!" moments you've seen?
I'm David, and we can do more damage this way!