If the keeper falls down and cannot get up,
the team should take away the keeper for 30 seconds.
If the keeper can go back to the field immediately after 30 seconds,
the other two players continue the whole game and don’t need to go back to the Goal.
Only if the keeper can not go back near the goal over 30 seconds, one player on the field needs to go back and become the keeper?
Since two players go back to the goal, it usually takes more than 30 seconds.