To get 10 turns of a 1 mm pitch thread needs at least 10 millimeters. For a hole, it may require another 1mm for the incomplete start thread from a countersink and another 1-3 millimeters at the bottom of the hole depending on the condition/design of the business end of the tap.
To clarify on the "doesn't work that way" the 1 mm pitch means 1 mm per thread, not 1 thread per millimeter. For unity the values are the same, but for any other pitch it does matter.