I had to cut into the floor in the same three places that I did when originally installing the cables a few months ago. Here's a photo from a few months back - during that construction - showing the place where the raw cables came up from the sub-floor:

And here they are now, safely sheathed!

Here's the location where they disappear downstairs:

Now strongly covered ...

But I had a problem with cable lengths. Because of the chewed out section, one of the original cables no longer has enough length to reach from the router down to the connection on the ground floor. And I can't replace it because the distant end of it is embedded under the flooring down there in the new shop! So although I really didn't want to do this, I had no choice but to splice a new connector onto the cable, and join it with a new short piece to bring the length up to what we need. That connection is safely hidden from the rodents, inside a metal connector box under the floor, where we can get to it if we need to.

After another hour or so of work to put the room all back together, I now have our internet all back up and running. And I was happy to see that speed testing on the spliced cable doesn't show any significant loss of bandwidth ...

Let's see what the invading army will come back with tonight!