Pfizer Sr. Scientist interview questions

The interview with HR was very smooth. I was asked basic questions about my background, salary expectations, date of joining, why I want to move. The interview with the Hiring Manager was dense. He asked questions about my background, skills, what the company is looking for, asked me to design an experiment based on a background he provided. The only problem was that he was not audible, there was a lot of noise around him which made the call a little uncomfortable.