By fell, do you mean the top caved in while baking? That sounds like it was over-risen by the time you put it in to bake. The "brick" sounds like the yeast was killed. These are usually dough problems, not baking ones; What bread recipe did you use? Do you have a photo? The bread should be a little denser than usual, not big and fluffy, but it should still be roughly within the range of store bread density. Interesting to hear, because I have baked several different types of bread this way and have had no failures - I figured it to be near fool-proof, but maybe there are more variables than I thought in this process. If your dough is fine, the only way I can see it going wrong is if you didn't let it rise enough in the pan in the pressure-cooker (or let it rise too much, I guess), and just cooked it as a lump of dough. It should be nicely risen before you bring it to pressure - then it should spring by about 20-30% while steaming. Compare the photos in step 1, step 3, and the photo of the whole "muffin loaf" on my cutting board in step 5, to get a feel for how the bread changes in size. It has not quite doubled in size between punching it down in the pan and starting the bake. Today I am trying to make a real sourdough from starter for the first time, baking one in my oven and one in my pressure-cooker. I'm excited to see how it works out.