When forcing an inward opening door, which side of the fork should you use?

Using the bevel side of the fork when forcing an inward opening door is the correct choice because the bevel is designed to effectively engage with the door frame and the latch mechanism. The angle and shape of the bevel allow for better leverage and force distribution as you push against the door to create enough space to gain entry. This side can easily slide into the seam between the door and the frame, making it easier to manipulate the latch or any obstructions in the way.

Other options like using the concave or flat side would not provide the same mechanical advantage or capability to engage with the door's components effectively, which is crucial when trying to force entry swiftly and safely. The V-shaped option is also not suitable as it lacks the necessary design that focuses on gaining leverage against the door's structure.