Hey Peter,
It seems like for the most part you have a connection between your work experience and your career goals with the exception of your most recent role. I would first recommend you re-evaluate if there is any connection to your career goals that you may have missed. Often candidates ignore functional skills like marketing, accounting, or financial skills gained and only focus on the industry and vice versa so that should be your first step.
Now if there was no oversight, honesty tends to work best in these situations, you can frame this most recent role as an exploratory role that did not work our or a risk where you bet that it was the right opportunity/industry for you but has not been. B-school is an opportunity to pursue your personal/professional dreams so if framed properly admissions will understand the side step