It was part of what was being argued
back here to say that given his leg was mangled, the imagery of glass shattering to show his limits being shattered, and the whole parallel of reaching the light to reaching his status as a warrior, he would've reached light speed right at the end
According to the relativistic velocity calculator,
Dabura's CE when traveling at 75% the speed of light is 1.3 gigatons of TNT;
When traveling at 90% the speed of light, it is 3.37 gigatons of TNT;
When traveling at 95% the speed of light, it is 5.72 gigatons;
When traveling at 97% the speed of light, it is 8 gigatons;
When traveling at 99%, it is 15.37 gigatons;
When traveling at 99.9999999...% the speed of light, it is 67.94 gigatons;
The closer to the speed of light, the greater the load.
By our standards, 10% the speed of light is already relativistic and close to the speed of light. Even at this speed, Dabura would encounter air resistance and be at its limits. However, its strength at this point would be around 13 megatons. 10% of the speed of light is pretty close when you're talking about light speeds. And getting closer and closer to 50-75% is already pretty bold, not lowball, but it completely explains why Dabura literally burns up due to the difference.
But screw it, even if Dabura's durability is 4 Gigatons. At 99.99999%, his legs are already destroyed by the strain. He doesn't need to reach the speed of light to damage himself and exceed his limits. Considering we don't know what his normal limits are, it could have been 20% SoL.
But I can say for sure that Gege, who usually tries to use mathematics, who created the Yorozu spheres of infinite pressure, wouldn't miss the opportunity to say that Dabura delivered a blow of infinite mass.