To force an outward-opening door, which part of the Halligan bar is inserted between the door and the frame?

In order to effectively force an outward-opening door, the adze end of the Halligan bar is the appropriate tool for insertion between the door and the frame. The adze end is designed with a broad, flat surface that allows for greater leverage when prying the door open. This feature is crucial because it provides the necessary force to manipulate the door's position against the frame, especially in situations where the door may be jammed or locked.

Using the adze end enables firefighters to create a gap between the door and the frame, allowing them to apply additional force to push the door outward. The shape and design of the adze end make it particularly suited for this type of action compared to the other ends of the Halligan bar, which serve different purposes. The forked end is better for pulling or leveraging, the pick end is useful for penetrating surfaces, and the bar itself aids in leverage but is not directly inserted into the gap. Thus, the adze end is the most effective choice for this specific task of forcing an outward-opening door.