I thought the modern US military was very big on process and tradition in the development of officers.
And for individuals with the right skills and experience, O-5 isn't unusual.
EDIT: Here's a random example:
https://www.reddit.com/r/Military_Medicine/comments/1468l1f/...
The somewhat famous quote "Alight here for the Home of Rest with Army Exemption thrown in", a familiar greeting to RAF's working force by Farnborough's tram conductors, is a testament to it.