Edgar Pons hit some of the debris and hit Honda Team Asia's Andi Farid Izdihar to take both men out of the race as well.
The commentators immediate said it was "a dangerous, dangerous place to crash".
"That was horrific," the commentator said. "It's just about the worst thing that can to riders, it doesn't get much scarier than that at Grand Prix level."
Bastianini was gutted by the side of the track as the carnage took place and medics, and the clean up crew got to work.
The race was immediately red flagged with 22 laps remaining with the race restarting for the final 13 laps.
There was plenty of worry for Syahrin but news quickly came through that he and all drivers remained conscious and suffered just a pelvic contusion, but the first scan didn't reveal any fractures.
Syahrin's team boss Gino Borsoi confirmed he was all right.
"The rider is fine, with many bruises, especially on the hip, but has always been conscious," he said.
Moto2 is the classification under MotoGP with riders using 600 cc four-stroke bikes.
The motorsport world was quick to react.
Freelance MotoGP reporter Simon Patterson tweeted: "Red flag in Moto2. One of the most horrid crashes I've seen in a long time. F***."
Jorge Martin was the eventual winner of the race with his first win in the category, having led from pole at the restart to the chequered flag.
But it was clearly overshadowed by the terrifying crash.
It just got crazier however with the MotoGP following suit with a red flag after Yamaha driver Franco Morbidelli clipped the front wheel of Johann Zarco's Ducati with their bikes crossing over the track as the field passed, narrowly avoiding disaster.
Again, the drivers avoided major injury with Zarco walking to the ambulance, while Morbidelli was put on a stretcher.
Morbidelli and Zorco were both declared fit.
Nine-time MotoGP champion Valentino Rossi was just as lucky, narrowly dodging between the bikes with oil even covering his bike after the race was red flagged.