This is quite a lot of money and Kevin Mandia obviouly made some right decisions in his life. But what is Google really after here? The employees (must be quite flutering to be valued at 10 million on average), the products, the marketshare?
So as long as they have amazing handcuffs on the CEO, it's probably more like $1M per employee and $100M+ for the CEO (if real handcuffs) + brand.
An independent Mandiant is amazing for the ecosystem, but so goes. Over all though, probably still net win for folks involved + community - Google getting even more serious here is great!