Responses
This is the link for the light novel: https://cookiepasta.com/
However, it is behind the manga. So we don't really know their thoughts yet.
I'll second that agreed on it
Since I haven't read the light novel of this installment of the Doulou Dalu/ Combat Continent/ Soul Land series (Has someone even gotten a decent way into translating Doulou Dalu II into English?) - as light novels tend to give extra insight in the characters' thoughts - I can't give a full and fair assesment of the fight...
But my current thoughts are as Such: The first death - Lin Xi - was truly a tragic accident. No one knew how powerful Ma Xiao Tao had gotten - not even herself. Although imo, the ref should have stopped the match there, but I digress. Now Chen Fei's death is a lot more grey. There are a lot of people at fault imo.
First is the ref. Yes, while the ref said that he couldn't guarantee any of the combatants' lives, failing to stop a second death is sloppy on his part - the text seems to imply that he was more busy looking out for the biggest talents of the Sun Moon Empire, rather than all the combatants.
Secondly, Chen Fei, even though he was the one who died, bears some responsibility for his own death. Chen Fei's inability to judge the strength of Ma Xiao Tao after it was fully demonstrated and rushing head-log to confront her without the personal strength, plans, and/or tools to make up for the difference in power - not to mention the fact that Chen fei was the only one who used his fists rather than a ranged attack - only further led to his demise.
Thirdly is Ma Xiao Tao herself. Here I'm going to use the "With great power comes great responsibility" argument. If Ma Xiao Tao knew that he Phoenix flames could go out of control again, she probably should have backed off and/or decided to just escape until help could arrive things might have played out differently.
Alternatively, since we didn't see the exchange of attacks that lead to Chen Fei's death it could also be possible Ma Xiao Tao warned the three to back off when she felt her Phoenix flames acting up and Chen Fei's rage blinded him to the fact that she warned them to try and save their lives and died as a result. However, even in this scenario, the ref should have been able to intervene.