The origin of the matter was quite melodramatic.
Despite his teacher's current facade of seriousness that mirrors a humble gentleman, he had his fair share of wild days in his youth, and this incident was a result of his romantic debts.
After completing the task in South City, that evening Mr. Ma took Yu Hang to the most famous local bar to broaden his horizons, but unexpectedly, they encountered an ex-girlfriend from long ago whom Mr. Ma had abandoned.
The moment she saw him, before even speaking, her eyes reddened, and she grabbed a bottle of beer and smashed it over his head, leaving Mr. Ma seeing stars and feeling dizzy.
But the woman was not yet assuaged. Grabbing a second beer bottle, she intended to continue her assault. Yu Hang, momentarily stunned, quickly snapped to his senses, unable to just watch his teacher be attacked.
He didn't care whether the assailant was a woman or even if she were an alien; it wasn't acceptable to crack people's skulls open like that!