[Spence]

R1 R2 1 out

Groundball to F6. R1 beats the throw to 2nd. F4 continues and throws to F3 for the forceout.

R2 assumes that R1 was out and 2nd base . After touching 3rd he starts to leave the field heading towards the 3rd base dugout.

At what point is he considered to have abandoned the base and is no longer able to either go back to third or proceed to home plate?

Does he have to be in the dugout/DBT?