Board Thread:Achievement Hunter/@comment-173.171.57.7-20140331045647/@comment-24853698-20140602030655

I believe the tunnel is for an unfinished Let's Play, most likely for episode 200. That is why Geoff doesn't want anyone to see what's in it. There is a nether portal somewhere inside that tunnel which is what Jack came out of during Episode 100 and why Geoff instantly said for Jack to close his eyes etc.