Coach, I agree, extending the situation to 1st base is a stretch and really not applicable. Here's another thing to think about. Runner is trying to break up a DP. But, keep in mind, chances are, by the time he collides with the fielder, he's out already, so, he's technically not a base runner anymore. This would end the discussion about a baseline. At least in terms of going to 3rd or heading back to 2nd. If he didn't leave the base path on his way to 2nd, and his momentum carries him past 2nd, it makes it more difficult to define the rule. It is not an easy dilemma to dissect. Even the play at home is still pretty nebulous. Catcher has to leave an open base path to the plate. This is constantly in debate. Catcher can't stand in front of the plate, but he has to make a tag. Runner can go as far to the sides of the plate to make some sort of hook slide to avoid the tag, but the catcher has to leave a clear path. Makes it much harder on the catcher to make the play. The interpretation of this has been changed several times already to try to make it more clear, but it is still pretty difficult to determine, if you ask me.
Sometimes changing one thing brings about other issues you didn't think about. I said it before, if Tejada wasn't hurt, this wouldn't have even been an issue. And I agree with others. I think he was suspended in order to cool everyone's jets when the series goes back to NY.