While we’ve got a bit of free time until the next strip, Lucranians.
The abandoned ship computer Wally talked to (http://www.gocomics.com/endtown/2016/09/16) told him that Lucranian ships are not allowed to visit parallel-reality Earths that still have living inhabitants, and that ALL of the Earths immediately bracketing Wally’s on both sides are dead planets. Additionally, the wars that wiped out those Earths were triggered by resource shortages (http://www.gocomics.com/endtown/2016/09/21). Wally’s war was the only one triggered by a mutation plague.
Yet, Aaron Marx had said that Wally’s was Marx’s favorite incarnation of Endtown, and to Flask, he said, “Where else could I have a post mortem chat with the villain of my favorite iteration of the Endtown reality spectrum?” (http://www.gocomics.com/endtown/2012/08/22). In the same strip, Marx says that Flask had killed the captain of the Lucranian ship she hijacked (in the other realities), implying that, yes, Lucranian ships have visited inhabited Earths before.
Finally, the conversation we saw between Wally and the abandoned ship’s computer was what Marx (http://www.gocomics.com/endtown/2016/12/12) wanted everyone to see. On the one hand, he’s saying that there are multiple realities where Endtown exists, on the other, he’s reporting the Lucranian ship saying that there is just the one, and the Earths in the surrounding realities are all dead. If we can’t believe him regarding parallel Endtowns and manned Lucranian ships not visiting inhabited Earths, why believe him when he has someone say there’s no mutation vector?