I am in a similar boat. 4th year TT at an R4 in a department in the humanities. My research has steadily become more science-y in nature and I am not at all content with my current job. Because there are very few jobs in my area and I would like to work in a related, but different, discipline, I am considering a postdoc to get the training that I would need to do so. Is this categorically a bad idea? What does someone in this situation have to gain by getting tenured, getting loaded up with service so they can’t publish much and ultimately getting stuck in a job that makes them unhappy?
Vane held a post at the University of London for 18 years, progressing from senior lecturer to Professor of Experimental Pharmacology in 1966 (at the Royal College of Surgeons). During that time he developed certain bioassay techniques and focussed his research on both angiotensin-converting enzyme and the actions of aspirin, eventually leading to the publication with Priscilla Piper of the relationship between aspirin and the prostaglandins that earned him the Nobel Prize in Physiology or Medicine in 1982.