0 --> "t", 1 --> "e", 2--> "s", 3 --> "t" 4 --> "\0".

if you point directly to 2 it will go further and further until it reaches \0 at 4. This results in "st"
if you only want "s" you have to change the array:
0 --> "t", 1 --> "e", 2--> "s", 3 --> "\0" 4 --> "\0".

cell 4 would be unused then.