Kommandoz Breacha Boy, and Into the Dark

Me and some friends have recently been getting into Killteam and playing on the into the dark terrain set. I had read the rules on Kommandoz and didn't really consider how the Breacha would work. The Ork player activated the Breacha and proceeded to move through a wall (which from the rules is valid as long as it is X thick). They then asked if that means that this section is now open?

I couldn't find any rules one way or the other, but it would make sense if you breach a hole in a wall with the Breacha it wouldn't just close itself afterwards, so they played on with the assumption that the wall section was now open.

Queue two more turns and the Breacha had turned the space hulk into swiss cheese, completely flanking and out manoeuvring the Tau player.

Both players were fine with it and had fun regardless, but I wanted to check if there are any rules stating one way or the other.