If Alex had the rats go back a little ways, they could re-connect, and THERE digging would reveal the tunnel proper, and two rather concerned rats. The further he dug FROM the lighthouse, the easier it would be to access the tunnel.
Closer to the lighthouse, but from another direction, a couple figures walked up.
"Not sure yet," the swarthy, non-Will one said, staring at the lighthouse as he approached it, "But it might just be leading me
here."
((figured I'd combine the exploration and puzzling threads, as Alex has evidence and Sean has knowledge. And Will was there, too!
))