It's not the anger that's cowardly, it's the refusal to try. It's taking any other path, so long as you don't have to risk your own stupid pride. Have the humility to accept you might not make the right call, but the courage to actually make it for yourself.
This adventure comes from a time when modules were a toolbox. One of the most popular modules from the era had a plot of "there's a bunch of monsters in some nearby caves, and they don't all like each other". Tunnels were blocked by debris, allowing the DM to connect it to another dungeon they wanna try. You might come back to the same dungeon a second time, and the contents of the room will change. A module is a starting point, but the DM continues the story from there.
If you don't know how to prep that, then the empty room is a boon. If you do, then the empty room isn't an issue. If you don't want to prep a campaign like that, then maybe this style of module isn't for you in the first place.
And we played the first thing that came to our heads
Just so happened to be
The best song in the world
It was the best song in the world