Money can make the devil turn a millstone. If it can't, it's because you haven't offered enough!
When the money's enough, there will naturally be people willing to take risks!
Right now, Ma San is just such a person, and he's ready. If something goes wrong or if Elder Xiang has someone backing him up, he can make a getaway at any moment.
One hundred and twenty thousand, that's enough for him to find a new place and live well, unlike now, just a small-time thug.
The key is, his actions are greatly restricted by Shi Bao.
"Damn it, at worst I'll just run away!" he thought to himself, "This life doesn't suit me, it's frustrating!"
He's inherently a fearless thug, with a particularly bold disposition, and when it comes to fighting, he's completely fearless.
This is also why he became a small gang leader at such a young age.
Similarly, it's also why the developer found him to handle this demolition, not just because he's extremely familiar with this area.
