Six at the beginning warns a querent against being the last one out. The reading concerns a withdrawal already under way in which this person occupies the exposed rear, and the instruction is unusually absolute: undertake nothing, in any direction. The commentary on the image supplies the reason, which is that calamity is avoided by not moving rather than by moving well. Somebody drawing this line is not being told to withdraw better. They are being told that withdrawal is not yet available to them.
The position explains why. A yielding stroke in an odd place has no resource of its own, and it sits at the floor of the mountain trigram Gen, whose whole character is stopping. A querent here usually knows the situation is ending and wants to be seen managing the ending gracefully. That wish is the hazard the text names, because a visible movement at the rear identifies the retreat to whatever it is retreating from, and this line has nothing in hand with which to survive being identified.
When the line changes, the lower trigram Gen becomes Li and the figure becomes Fellowship, King Wen 13, in which people out in the open hold together by a common bond. Read from the tail of a retreat, that destination reframes the counsel entirely. What ends the exposure is not distance and not concealment but company, and the stillness this line demands is what lasts long enough for the others to be reached.