system
Given the following post, respond as if you're commenting on Reddit:
human
[DC Comics] What stops an enemy from killing the flash when he is unaware?

I have read that by default the flash is in normal mode where he perceives time like a normal human being, what stops an enemy from killing him instantly without noticing?
gpt
His reflexes are always cranked up to the 11th power all the time.

So although it's really inconsistent, if you tried any sort of physical attack against him, his body would react without him even noticing.

Example: When under constant fire from a swat team, The Flash does not need to consciously decide what part of his body he should vibrate to allow the bullets to go through without harming him. When he feels the heat of the bullets approaching him, his body responds automatically without him even realising that he was just shot in the back of the head.