Ah-- now I can see how it might have happened. If Lex actually waded out into the water with her, taking advantage of her increasing drowsiness, he could have gotten her far enough out so that, disoriented, she'd swim away from shore and there'd be little chance of her washing up on the sand further down the beach. And her disorientation could have been enhanced by the coldness of the water after the initial first shock, I suppose. And his actions on the shore just before they took their little swim? What a nasty thing for Lois to have to keep remembering!
This was hilarious--
I mean, you’re not some moronic pop star who doesn’t know what she wants and marries someone on a whim and divorces him two days later,” he said dryly.

Now, whatever she might know or not, she knows something's up-- and she'll dig 'til she finds it!!
So-- now we sit back and watch an investigation? Or is that to come in the third story? I do wonder how Lois will get out of the marriage now. She can't let on she's alive, not right away-- Lex is too powerful for her to just step up and accuse him of attempted murder, isn't he? Of course, Lois has the considerable talents of Clark-- both super-powered and non-super-powered-- to add to her own powerful investigative talents-- I almost feel sorry for Lex. But only almost!
~Toc