I clicked through and read the article, but I haven't searched the literature yet. However, "vaccine platforms" are a real thing. US DOD has funded some work for development of modular platforms to facilitate rapid vaccine production. It's entirely possible that a nimble company with a good platform already in hand could make a GMP prep of vaccine in 90 days. Performing all the required tests on the GMP batch of vaccine is what would take too long. If I were this company, I'd be trying to do the same thing. I'll be pleasantly surprised if they are successful.