Buy-in offer seems predatory - need reality check

Owner is offering me a 20% buy-in for $400k. Practice does about $2.5M annually, he says EBITDA is around $600k. The terms: - $400k upfront (I'd need to finance) - 20% of profits after that - 5-year buyout option for remaining 80% - Non-compete within 10 miles for 3 years if I leave This feels like a lot of money for 20% and the non-compete is scary. Am I being paranoid or is this actually a bad deal?