[When you're made of Adamantium the way he is, you don't 'float'. In fact he's a pretty damn good anchor if nothing else, but that doesn't help him much in the grand scheme of things today. It feels like a bad omen all morning long and Logan knows he's a shit swimmer - his strength may keep him afloat in the more dire of moments, but exhaustion'd be quick to follow. His mutation wouldn't let his drowning kill him, at least.
With that beautiful thought on the forefront of his mind, he will gradually progress to higher ground with the water level rising. He knows the evac plan but he's not in a rush to take someone less durable's spot on speaker island. There's something about the swirling water that's making him feel edgy, however.]