Peter left the door open, and John got inside. While he wasn't parallel during the braking or entry to the corner, he was absolutely parallel just before the Apex.
Both drivers kept it tight, and both drivers left a car width for each other.
I think that John's early throttle on the Kerb (you can see the RPM jumping) pushed him understeering that "1 meter" as he described - which was the differentiator between a great racing by both drivers, to an unfortunate incident that ended both their races.
That's why I pick CAT1 for John, for that early optimistic throttle, but overall great racing from both drivers.
John ChikoCategory 1
Before the impact, John was faster with the draft and closed the gap getting side by side little before the turn,
even though I cannot know for sure but I believe Peter should be able to see John and be aware that he is getting his inside and get spotter notification of car on the left.
John was also able to brake later and take the inside line, John has not done anything wrong by all means,
Up to the point of the impact, it seems the main cause is that Peter not giving enough space to John as he could have taken a wider line.
But after the impact, it seems John's exit could have been more tight as he seems to be getting wider than expected, but that could have been as a result of the impact.
In any case, it's very hard to determine if one driver is more at fault here than the other, that's definitely is not John fault
And I think we can classify it as a racing incident Cat 0
Peter and John go side by side, John keep his left with a little bit understeer and Peter come very close and touch John wheels
Peter can take more right to avoid.
The accident was on turn 5 and not 10. Before getting into the braking zone for the turn, John was completely behind Peter. Then John did late braking and took inner line - Peter was just following racing line toward the turn's apex. Peter could see John there but still closed the door. So in my opinion - both drivers are to guilty for this accident, but John was doing the passing move, so his blame is bigger there.
John ChikoCategory 3
Peter GreenCategory 2
although Chiko had understeer he would've managed to make the corner without contact with Peter, but Peter tried to force him to go narrow as Chiko said(and that Peter admitted in the chat group). I think it was a miss communication, even if Chiko did make that small mistake of braking a bit to late I think it was a racing incident because he managed to control the car and it seems that he would've made that corner with no trouble, so I give them both CAT0.