re: NASA is about to perform another test on Space Shuttle main engine the RS-25..

No.

However, it is cool that the test stands have underground passageways that link them to the test control center for each cluster of stands.

I was down there the other day and it reminded me of video game. Dark as shite, very narrow (and wide.. haha) pipes running down both sides and puddles of water all throughout the tunnel. I was half expecting a zombie or ghoul to jump out and attack me.