It’s an interesting scenario that I suspect quite a few of us have thought about away from the aeroplane. Many busy airfields regularly cross traffic over active runways so it’s something that is familiar but that rarely goes wrong in such a spectacular fashion.
If you’re on the runway, at what point do you recognise that someone is going to infringe rather than hold short, being used to aircraft doing the latter? There is a short window available for a very big decision and it has to be done mostly on feel because there is no time for any sort of calculation, especially as there isn’t much data to put into it at that instant.
An initial analysis shows that they *might* have been able to stop but there are a lot of inherent assumptions about the timing of the reject decision and how well the RTO would have been handled in the circumstances. Well over 100kts and coming up on V1 you are eating runway up at quite a rate. Steer onto the grass if you think you’re going to collide? Depends on what else is on the surrounding taxiways, as you’re effectively going to lose control at that point.
It’s a horrible decision to have to make but it needs to be made. Nothing was broken in this case so it was de-facto at least adequate. Optimal? Who can say, given the amount of variables at play...