I found interesting in yesterday's call that Elon brought up the door seals again as a challenge. He also say that a difficulty in building cars is that it's difficult to anticipate what the final challenges will be/who the worst suppliers will be. To my knowledge, the seals were already a challenge a year ago- so easy to anticipate. I wonder why it's so hard. The only thing I can imagine is that in a conventional door that the metal pushes against the seal closer to the normal force direction whereas in the falcon doors the door has to slide against the seal sideways in more of a shear force direction? Will be interesting to see how this pans out, and whether seal reliability and or leaking will be an issue in the future.