What happens in the following case:
- A batter hits the ball and it touches the ground.
- They run and touch first base.
- Thinking the ball is far enough, they begin advancing to second base.
- However they realise they cannot reach second base.
Can they retreat to first base and occupy it? Or can the defending team tag the unoccupied first base for an out?
The same question in another way: what if the batter ran very quickly and slides to reach the first base then after safely touching it kept sliding away from it (without intention to advance but he was just sliding too fast). Is it still his base?