I have seen this happen to many people (myself included) when you go into the opening on the other, at the end, to the right, there is a door. Using the fountain as cover, eliminate the hostiles. There are hostiles in this area, including one carrying a Hutchinson A4. Follow Mitchell and he will lead you to a big area with a fountain in the middle of it. Now, this next part can be a bit of a headache. Run forward and climb the ladder to complete the underground section.ΔΆ. If you roll fast enough, you can avoid the falling debris in front of you and continue on, if not run forward an vault over it. Once you have regained control, continue on this path. You will notice a low wall at the far end. Continue on down this path, taking a left at the end. At the end of this section, you will see a wooden barricade to your left. Vault over the barricade using the Triangle button, and continue on. You will see a low barricade in front of you. Be warned, he will slam the gate in that section. You will see Mitchell on the other end of the corridor, running through an opening. Run to the end of this corridor and make a left. Once you have cleared the area, smash to the wooden gate blocking your way. You can also eliminate all three of them, but you have to be quick about it or Mitchell will get away. My recommendation is to ignore the first two hostiles and concentrate on the one blocking your way. Be warned, there are hostiles in this area. You will find yourself in a big open section next. Press the X button twice to bust through the gate. You will see Mitchell slamming a gate in front of you. As you descend these stairs, make another right. Follow this corridor to another set of stairs. To start with, go down the two flights of stairs and turn right.