So, aside from my base in the lake, as I mentioned, my base was underground about 30 blocks down. The ladder leads to a long hallway where they come to me in a single file and I pick them off one by one. If I encounter a spider and the opportune chance of reloading, I get hurt quite a bit but still manage to survive.
So I decided to put an iron bar in between to hopefully get out un-scathe.
But...instead of the Z's going down the ladder and attacking me straight, they stopped in the middle of the ladder and tunneled their way to me. I thought I am screwed if they then tunnel down from the ceiling.
To my disappointment, the first wave was stuck there. They were just on top of me but still below ground. Until the blood moon ended at 4:00am and I had to go up the stairs and meet them.
The AI of Z's needs fixing. They are forced to go to the path of lease resistance but they can't tunnel downwards. But they stand more of a chance if they overrun me in the hall.
So, there you go, another way/loophole to get away un-scathe on a blood moon.