I'm assuming there has to be a limit set by NASA of how far astronauts can be from each other for their safety. If something happens to an astronaut's EVA suit, the second astronaut can use the "buddy system" to share their oxygen supply, hence the need for a limit.
The OPS [Oxygen Purge System] provided a maximum of about 30 minutes of emergency oxygen for breathing and cooling. This could be extended to 75 to 90 minutes with a "buddy system" hose that used the other astronaut's functional PLSS for cooling (only).
Question: Was there even a limit of the distance the astronauts are allowed to be from each other during a lunar EVA? If so, what was the limit?