It looks like base overlays are only partially unloaded for the camera move that precedes the cutscene for the Great Escape. The area where I had the camera centered when the rocket took off had the pipes unloaded, but not their contents, and the out of frame pipes were still there. I was in the pipe overlay view when the rocket took off, so it might happen for other overlays as well.
Steps to Reproduce
Launch a rocket to the temporal tear and be in an overlay (pipes maybe others) when it launches and triggers the cinematic.
This issue has not been confirmed by a developer yet.