Not everything that happens in the course of even the most meticulously detailed story has to happen "onstage:" that is, in view of a viewpoint character who’ll take note of it in a fashion the reader will hear about as it happens. "Offstage" events -- events that occur outside the narrative stream and are referred to only in passing during a narrative thread -- are often quite important and can be given quite a lot of punch by the proper handling.
I tried this out in On Broken Wings and was pleasantly surprised by how well it came off:
Five large motorcycles in a tight one-two-two formation roared eastward on the New York State Thruway, cutting through the chill air of the mid-March afternoon at seventy-five miles per hour. All five riders were young. All were tall, broad-shouldered, and well built. All wore jackets of thick black leather, each of which had a cloth depiction of a bloody cleaver pop-riveted to its back. All the other traffic they encountered on that great highway moved aside to let them pass.
In theory, they weren't going anywhere in particular. They'd wandered the Northeast for six months. They were supposed to be looking for a place to make their home base. They were half-afraid they'd find one. Wandering suited them; it was part of why they were together.
Pete Gottfried and Al Marshall rode at the back of the convoy. They were both twenty-nine, and had already lived the road life for more than a decade. To be in motion was the sum of their desires. To be at rest was a torture beyond anything else they knew. Wherever the leader pointed, they would go. Whatever he commanded, they would do.
Mac Swanson and Carl DeShaies were in the middle. For them, the road life was both means and end. Twenty-six year old Mac was wanted in his home state of Montana for a murder he'd committed in the course of a convenience store holdup. Twenty-seven year old Carl was notorious among the citizens of Orem, Utah for his ways with their little girls. They had met in flight, had crossed the country seeking a haven, and had pledged their allegiance to Tiny and his Butcher clan together more than six years ago.
Rusty McGill rode alone, about fifty feet ahead of his diminutive pack, his shoulder-length red-brown hair whipping in the wind. At twenty-five he was the youngest of the group, but he was the undisputed leader. Since they first bonded, he'd become the least talkative as well.
The "diminutive pack" Rusty leads formed offstage, in consequence of a schism within the Butchers, the larger pack of which the five had once been a part. I couldn't see a reason to narrate the process by which Pete, Al, Mac and Carl decided to throw their lots in with Rusty, so I skipped from the schism straight to this point in the story. The ongoing narrative struck me as tighter and better paced that way.
In Shadow Of A Sword, I did it again:
Sumner rose from his chair as Christine entered. “Are we ready, Chris?”
I’m not sure I like the look on her face.
She closed the door of the waiting room soundlessly behind her. “Maybe. Steve...you should brace yourself. It’s quite a crowd.”
“Bigger than LA?”
“A lot bigger.” She hefted her new, ultra-ruggedized laptop. “I’m not certain about the crowd control. They’re pressing the forward barricades pretty hard.”
Only a security type would fret over a huge crowd at a campaign stop. Well, that’s why I have her.
“Well, are you ready?” She nodded, and he indicated the laptop. “Why are you bringing that?”
Without apparent thought she said, “The case will stop a bullet,” opened the door and gestured him through.
There was an earlier exchange in which Sumner and Christine discussed getting her a laptop, but needless to say, showing two adults shopping for a computer, even a slightly exotic computer with a hardened steel case, wouldn't hold the typical reader's interest. So I skipped it. What I discovered by handling the exchange that way was that I could use it to sharpen the reader's perception of Christine. She's toting her new computer along because it might come in handy in saving her client's life. She's ready to use it that way, regardless of the damage it might incur from such an event. Thus, her offhand statement to Sumner became an element in her characterization: an amplification of how thoroughly she relates everything around her to her primary duty of protection.
In a way, this is about the importance of making sharp, confident transitions between scenes that are separated in space or time. Lawrence Block calls them "fast cuts," and emphasizes how they serve the reader's sense of the narrative's pacing and urgency. But even the fastest cut will omit the events that occur within the omitted interval. If those events are at all important to the story, you can allude to them in a subtle fashion without fearing that your reader will cry foul. If they can be employed in some other way, as for example in the scene from Shadow Of A Sword cited above, why not?
You don't have to depict or explain everything in terrifying detail. If your reader is well matched to your story, he'll invest enough imaginative energy in it to fill in what you've left out. Trust him!