This seems out of place given the rest of the imagery in the credits. Does anybody know what the relevance of this scene is supposed to be?
There is no relevance, other than the shot was a replacement.
From an interview with co-showrunner Katie Jacobs:
Q: "Are the opening credits images in “House” visual metaphors for the roles the characters represent in the show?"
A: "Initially when you do a title sequence you are trying to separate yourself out from every other show. You look to establish a unique visual brand along with a distinct sound. The shots in our sequence don’t have any “specific” meaning, but I do like the fact that in the last shot, David Shore’s name is where the head would be on a body. He is the brains of the show. Some images we initially wanted to use included a shot of a cane and one of a bottle of Vicodin. The network was not on board with those two choices and requested that we replace them. As a result the image with Jennifer Morrison’s name became the shot of rowers on a river — we needed another shot." (source)
So, it would seem that Morrison's name was originally to be shown along side a cane and/or a bottle of Vicodin,
but, because the network wasn't too approving of such an opening image, they had to change it. And, although the river shot does stick out when contrasted with the few previous images/animations, the very first shot of the show's opening is an aerial view of the hospital, so, at least there's some consistency..