Volume automation was used to level the dynamics of the dialogue. The dialogue was to be clear and distinct. It’s not a realistic approach, but it serves the purpose of a focused message.
The music was mixed to specially support the dialogue. The soundfield has space in the middle, and the reverbs used are extra dark so that they don’t overlap too much with the voice frequencies.
I also was the recordist at some of the shootings, and cleaned the dialogue of the ready film from noises and disturbances.