The 30-minute FP4 session ahead of qualifying was brought to a halt just under seven minutes in when Rins was forced to ditch his GSX-RR after it burst into flames.
The three-time MotoGP race winner’s bike had developed a small fire at Turn 10 before it worsened as he rounded Turn 12, by which point he pulled off and abandoned the Suzuki.
A clean-up operation had to be undertaken by marshals for oil left on track from Rins’ bike, with Pramac’s Johann Zarco – who qualified third – crashing on it at Turn 10.
Unharmed in the incident, Rins explains there was a problem with a tube carrying oil and admits the moment was “scary”.
“There was a problem with the tube where the oil goes, they already checked,” Rins, who will start eighth, said when asked by Autosport to explain his FP4 fire.
“But sincerely corner 10 I had a small rear scary moment, slide.
“Then I looked on my boots, on the tyre [for oil], but everything was under control.
“I continued pushing and immediately in the next corner I lost it [the rear] again and I go off the track for my security and the security of the others.
“Then, when I saw on the bike, I saw all the fire and it was a scary moment because what went into my head was, ‘Alex, jump’, because maybe the bike explodes.
“So, it was not a good moment.”
Mir "will not be able to finish" Indonesian GP
Rins’ team-mate Joan Mir had a miserable qualifying in Indonesia, after a crash towards the end of a scrappy Q1 left him down in 18th – his worst starting position since last year’s Emilia Romagna GP.
Talking about his day, Mir said he cannot find a good set-up and is “really on the limit”.
“It was a really, really hard day for us,” he began. “Looks like we are not able to find a good setting and the one I am able to feel a bit more comfortable on, I’m riding really, really on the limit.
“We are not strong. We are struggling a lot, so we have to continue trying things, to try to get better. It’s difficult.”
A key change this weekend is the reintroduction of a tyre casing from 2018 to better manage the extreme heat at Mandalika.
This has caused problems for some riders, chiefly the Hondas, with Mir admitting he has “less grip everywhere” with the tyres brought to Indonesia and is unsure he will even be able to finish the race – though isn’t sure if his grip woes are specifically down to the old casing.
“I don’t know if it’s that new casing or the track with the new casing,” Mir added when asked by Autosport how the new casing is affecting him.
“In Qatar I was always complaining about the grip, so with this tyre we have less grip everywhere: going into the corners and the exit.
“Now I’m in a situation that going into the corners is something that I’m not able to do with the correct speed.
“Then I have to use the front more, and then I have all the big moments that I had today. So, we are a bit out of balance and we have to find the way.
"I will be not able to, riding in these conditions, finish the race.
"Honestly, I think I will crash because I’m riding too on the limit every corner and like this it’s really easy to make a mistake.
"It will be really, really hard if don’t improve. So, I expect we can improve because if not it will be very hard."
