tell them its a family emergency if you have an interview. If you hate your job so much, why are you worried about losing it? At worse u find a job thats just as shitty, but chances are u will find a better one.
Your job dont give a shit about you, why give a shit about them? They dont give a fuck what ur going through when u need the time? So reverse it and tell them to fuck off if they need you. its a 2 way street and employee appreciation is key to a low turnover rate.
Trust me, if you quit the bank, the world will keep turning. If they need you that bad, they wont fire you.