Lutron Electronics Project Mechanical Engineer Interview interview questions

A two part interview divided 6 hours. 1st part is three hours (1 hr and 30 minutes technical interview followed by 1 hr and 30 minutes real world situation interview). 2nd part is two hours (1 hr problem solving interview, 30 minutes behavioral with engineer, 30 minutes behavioral with HR). All of the interview was covered over video call. The technical questions were fairly easy to answer, however the real world situation interview was confusing . The problem solving interview asked me a difficult public health question even though I have never really worked in public health before.