Advice Needed for Investment Bank Employment Situation

Hey all, need some advice here. Incoming analyst at a global IB firm starting next Monday. Very stupidly have yet to quite my current job for various reasons. The first week at the IB is pre-study/ pre-work time that is remote and in my head I would love to give my two weeks on Tuesday and finish out my day job after spending 9-5 doing the pre-study time for the FINRA exams without telling the Investment Bank. Does anyone know what IB typical employment rules are? I am assuming that you have to run other business activities by them, but considering I am not on the desk I am wondering if I can somehow get away with this without asking HR or stiffing my current employer on short notice.  I know I am an idiot for putting myself in this situation in the first place but anyone ever run into something like this or have any advice? Would prefer not getting HR involved unless I have to but also do not want to get fired from the IB for violating policy once I quit my current job.