Immediate dead ball?

[greymule]

At the moment, I can't seem to remember how to make what must be a simple call.

Abel on 3B, Baker on 2B, Charles on 1B, 1 out. Infield in. Daniels hits a one-hopper to F5. At the same time, F6 obstructs Baker.

Is this an immediate dead ball? In other words, do we assume that Baker was the runner being immediately played on? Or, since F5 had four possible plays and hadn't yet chosen one, do we wait and see what he does with the ball? (That is, if F5 plays on Baker, we call a dead ball and OBS. But if F5 throws the ball away at home or throws to 2B for the force and subsequent double play at 1B, we let the play stand.)

What if F5 started to run toward 3B (a play on Baker) but then threw home for an out?