I read the discussion Should CQRS Command perform a Query?

But I don't understand in witch database can perform the query. Because I have two distinct database (one for read and one for command).

If I need to take the customer info I need to read from the Write Database? It's a correct way? I think yes because if I read from Read Database I need to inject the reference to ReadModel and ReadDatabase and I lost the SEGREGATION, right?