Thanks for the update. I will try to remove those dangerous blocks from the server map later with McEdit.
I tried to go to the danger zone from another computer (Ubuntu Linux) with another player, same disaster happened.
Attached log again.
Not yet. It takes a year to get close.
Crash Report
There's a redstone powered lighthouse nearby built by a mate. Might it be the case?
Log file of recent activity
No I can't anymore. Even I restarted the server :/ It keeps throwing me off with NPE-s.
Rebooting the server did not help 😞
I suppose this issue might be the same as the one reported here https://mojang.atlassian.net/browse/MC-5027
I was able to fix it by teleporting very close to my redstone powered lighthouse and stop it working. Interestingly, when I appeared there the game became responsive again so I was able move. Now it's fine again. The world is saved!