The library has now made the Advanced Version available to members of the campus. When creating a new individual account, users must be on campus, logged in with their PassportID if off campus, or connected by VPN. Registration details are on the library's blog.
Non-AMC campus members can still register for access to the Basic (free) version: https://www.quetzal-search.info/
A Review of Quetzal: A Linguistic Search Engine for Biomedical Literature by C. Tobin Magle, Biomedical Sciences Research Support Specialist, Health Sciences Library
free/open access resource