Did I break 'A Study in Fear'?

I just completed the side quest 'A Study in Fear' involving a certain student of Indy's (don't read if you don't want minor side quest spoilers), and did it to the point I am exiting the temple. However, I seem to have broken it by not actually ever opening the Sarcophagus. I am currently 9/10 on objectives completed with that being the last objective. I think I broke it by managing to bring a shotgun with me through the climbing and squeeze points, and when I got to here, I saw a breakable wall, so I flipped that bad boy around and swung it, expecting to find something behind it. However, that triggered the water event that makes this room inaccessible for the rest of the game.

Am I borked?