Docker-Selenium-Behat miss-configuration, need Docker export for help

We have Selenium configured in our docker-compose
We have configured behat to use selenium
However, when we run the tests, we cannot access the local site via selenium

Details here : https://docs.google.com/document/d/1EL5U8Muvu7hDw_DQcmj56080JM0ThpLP7eh8HUedoUo/edit