It's possible this is unrelated to betweenlands, but it's never happened to me before. It also happened when attacking a wight that was possessing me. It got frozen on this frame:

notice the brown squares, idk what those are supposed to be but I assume it's related to the bug

It stayed like this for a bit. During this time I tried to take a few screenshots, which do not appear in my screenshots folder. After some time, the screen changed again:

After some time I noticed music and cave sounds were still working, and when I clicked esc the mouse would appear and sounds would stop, so the pause menu was opening. I clicked around to find the exit button, and the click sound played. After a bit the menu music started. I could close the game like normal from here. When I loaded the world again I was in the same place but with no wight (the fact there's also experience in the first screenshot makes me think I killed it right when the game froze, but you can also see the wight in the screenshot???).

My latest.log doesn't seem to have anything special, but I figured I'd post it anyways
latest.log