Board Thread:Theories and Speculation/@comment-34656247-20191119070420/@comment-3568954-20191130232741

the ability to activate a jutsu is in itself a speed feat. if someone for example was standing still and a light speed attack was activated and the shinobi activated a technique to turn there entire body into unbreakable rock before the light speed attack hit them than that would in itself be a speed feat. its an application of reaction speed. Obito's ability to activate Kamui is unmatched by any of the people in this question. he was able to fight on par with Minato when he was a teenager. it doesn't matter if any of them can run faster than him, punch faster than him, kick faster than him etc etc. all that matters is that the activation of his Kamui is incredibly fast.

on a side note: if he were to get surprised and someone hit him with amaterasu he wouldn't need to absorb it. he would just need to phase right through it. his screaming and yelling was just an act