Size of enclosure vs number of Box turtles

I'm planning on building an indoor enclosure for an Eastern Box Turtle, and was wondering how many it could accommodate comfortably. The dimensions will be 4'x3'x2'. I was originally thinking to just get one, but now I want to look into possibly getting two. My apt isn't that big, so I cant make the tank bigger.

 

Its big enough for two.

 

I figured it might be, cause I know eastern boxes are small. thanx