Explain why transferring or taking a temporary leave would not have worked and helped your personal situation. Make sure that you explain what steps you went through to consider other alternatives. They need to hear that you really thought things through and couldn’t come up with any other alternative.
Before you quit your job, you would have given your employer your grievances. This gives the employer the opportunity to fix some of the issues that you may have. When you decide to quit, you should notify your employer of your last day giving them notice that you will be leaving. Explain that the final notification was the last of several conversations where you and other tried to express concerns and that your employer never took action on those complaints. Of course you know they cannot change every concern you may have, but they have a duty to follow up with you on the reasons why and what they will do to help your situation.
If you were unable to give notice prior to leaving, stress the sense of urgency you felt by having to leave your job. Tell the unemployment interviewer that you would have liked to give a notice but the situation demanded an immediate action or that you were subjected to great health and safety concerns.