[quote=@IncredibleBee]
Al is a professional adventurer who makes his living clearing out ancient ruins and killing monsters. How's it a coincidence if he of all people was in an ancient ruin full of monsters?
[/quote]

Because it just so happens to be a dungeon that is featured in the roleplay first-thing. Any time a character's introduced and able to say 'done it before' on some remarkably specific plot element is lazy writing, unless they were sought out for the purpose of having done it before.