Hall of Infinite Doors

The track abruptly stops up ahead. When the cart reaches this end, it stops as well, almost as if the crew who was working on it was pulled away or taken away, by someone or something...

Suffice to say, it looks ominous. You get out of the cart to have a look around and then the cart starts rolling away back towards the entrance. Looks like you are going to have to proceed forward on foot...