As someone who is already in the corporate workforce, the idea that the uke needs to sleep around to find a job is just a major turn off. HR is NOT YOUR FRIEND. Your boss forcing you to give him sexual favors is the literal definition of workplace harassment.
Maybe it's just a Korean work culture thing, but I would resigned from the company and not looked back. Trashy workplaces like that are a stain on your career anyway. If another interview has to ask why you left, just say that the company culture and your work ethic did not match.