The dragon taking a couple minutes more than the man is what took so long. The exposition was replaced by what the witch said, who took his job after you guys Killed him.

I did my post from the perspective of the barkeep first seeing it and it's first roar. There's nothing that would imply he stealthily warped past other people who might have seen him first, unless you mean he should have been stopped to fight them before he got to the clearing, thus interrupting my last part of the post.