Thank you!

Well, even if both of them survive the end, I think it's disturbing enough. After all, Draco will need years and years of therapy to overcome this.

The perfect maze, with a willing victim, would grant immortality. Draco was not willing (the Unspeakables tried to make him be by putting him under Imperius, but it didn't work). That screwed up the maze. So there's no danger of Harry and Draco becoming immortal.