Formula One can learn an important safety lesson from Chinese driver Guanyu Zhou's huge British Grand Prix accident, according to Mercedes driver George Russell.
The Briton was involved in the opening lap accident that sent Zhou's sparking Alfa Romeo skidding upside down along the track before it flew over the tyre wall and became wedged sideways in a gap between the catch fence and barrier.
The rookie said later his life had been saved by the titanium halo head protection system.
"It was horrible, in that position he was stuck there, (there was) nothing he could have done," Russell, quickly on the scene after leaping out of his stricken car, told reporters at Silverstone.
"We need to think to avoid a car being stuck in such a fine gap," added the Grand Prix Drivers' Association (GPDA) director.
"The space between the barriers and the metal fence and he was just stuck in there, nowhere to go. Yeah, something to learn."
Had the car caught fire, as was the case with Romain Grosjean's Haas that penetrated the metal barriers in Bahrain in 2020 with the Frenchman able to quickly extricate himself, there would have been no escape.
On the opening lap, the Alfa's tank would have held more than 100kg of fuel.
Former racer Anthony Davidson, now a pundit for Sky Sports television, asked why there was a gap between fence and barrier and questioned the apparent failure of the Alfa's roll hoop structure.
Television images indicated the rollover bar had been ripped off and the halo was carrying the load.
"There's photos I've seen of the aftermath of the crash where the actual roll hoop seems to be missing," said Davidson. "That really didn't do its job, if you think about it.
"The roll hoop should be as strong as the halo, staying intact at all times and protecting the driver's head from impact, and it didn't do it. So they'll be asking questions of that."
Ferrari's race winner Carlos Sainz had no doubt the halo played a vital role.
"We sometimes criticise the (governing) FIA, but in these cases you need to give it to them how much they've been helping us," said the Spaniard, who highlighted also how the halo had worked in a big Formula Two crash on Sunday morning.
"What happened with the Halo, today, they've saved probably two lives," he added.