Voted for Willst du lieber durch den See schwimmen / If you prefer to swim through the lake (53).

Walking around the sea would take quite a time and the attackers would go that way, too - so not the best solution. Levitation would be fast but you're quite visible above the water. If seen you could be attacked and have no place to hide above the lake. That leaves swimming - you (hopefully) won't meet the bad guys that way, are less visible from the shore and it should be faster than tip-toeing through the woods around the lake.