1. Grab a tourist map.
2. Unfold it until you get the full map view.
3. Press ESC twice.
4. See that the map is folded out animation-wise and the full map view is gone. This is the point where you can't take anything else in hand.
Undoing it:
1. Hold right click to "take aim".
2. Punch with left click.
3. The map should unfold and now you can do actions as normal again.