Standard separation between aircraft is 3 miles, not 1 mile.
Please note that these jets flew in the opposite directions, and the Bombardier jet was totaled after this mid-air non-collision.
It was a wild ride.
In 2017, a Challenger 604 business jet was passing under a much larger and heavier Airbus A380 over the Indian Ocean. The A380 was flying 1,000 feet above in the opposite direction. (This may seem dangerously close, but a separation of 1,000 feet is standard procedure.) The smaller jet rolled over at least three times, injuring several passengers. Its cabin looked like a bag of Halloween candy dumped out by a kid, and while it managed to make it safely to an emergency landing in Oman, it was written off. The G-forces it endured exceeded the structural limits of the aircraft.
What had happened?
Two words: wake turbulence. The smaller jet had been caught in the vortices generated by the huge A380. Fortunately, pilots actively avoid situations like this one, and wake-turbulence incidents are very rare. But they are serious.