why would this door be here?

[KeeperOfTheCode]

Originally Posted by MacIronhawk

What would be interesting is if you could go into the building through there, now that'd be a big mistake on their end.(since there's only one door on the inside)

You can get in through there. It just dumps you in the middle of the room.

[Matthew Sternrage]

It kinda actually puts you near where the La Bodeguita backdoor is located, but a little more forward. The Tavern is also on the Starting Tutorial island, Rambleshack.