<step one>
Talk with AIKO about freeing Bob from his brainwashing after having reintroduced the AI to SISSI's systems.
For more information about AIKO's infiltration, click here.
<step two>
On a weekday, go to the alleyway near your work before 19:30 (seven-thirty PM) and lie in wait to ambush Evil Bob.
<step three>
When Evil Bob arrives, you will have two options: challenge him to a duel or ambush him. There is a third option to abort this step if you are unready to confront him.
If you are attempting an Ambush, you will need to pass a Martial Arts > 15 skill check to lock Evil Bob in a rear naked choke. Unfortunately, he is too large and too strong to be defeated that way and will chuck you into a dumpster. You will need to try a frontal approach on another day if this happens.
<step four>
To defeat Evil Bob in a fight, you will need to have ALL of the following:
Stamina >= 20
Strength >= 20
Dexterity >= 20
Martial Arts >= 20
If you do not meet all these requirements, Bob will win the fight. If you have three willpower to spend, you can stay behind after the beating. If you do not, you will flee. Staying behind or winning the fight will continue the scene, resulting in Bob being freed from his brainwashing.
<alternative method>
After completing step one, you can ask Kurt at Café Newtype IV for help with beating Evil Bob in a fight. He will agree and fight in your stead when you go to the alley. This will also result in Bob being freed from his brainwashing.