keisenzh Slow mo, slows down time overall which allows you to do one....maybe two actions like close your coat or turn around before your caught. Although if your detection risk is too high then you'll struggle even one action. Apart from that I personally find slow mo to be useless since if you need time to think you can always pause the game as you do all other actions so often you can easily start to get bored that you don't need to see them in slow mo.
The skill that auto activates it is purely there as an method to attempt to allow you to do one last thing to save yourself before caught which is best used when blindfolded and handcuffed while flashing (presuming you didn't drop your coat) or when in hard mode. If slow mo auto activates and you don't want it to then just press the slow mo button, it shouldn't activate again unless it's re-triggered.
I do wish there was an buff applied to this via equipment or an extra skill that allows you to less slowed, resulting in yourself being able to move out of line of sight if you don't have your coat on/are fully exposed. As after a point of the game you can just disable the skill however there's no benefit since you don't lose RP from having it enabled.