Returning to the exact point of departure is easiest; the coordinates are more certain. There's a brief margin of error—going forward only, though. Arriving before you left is both inadvisable and, with the current transporters, extremely unlikely to happen. You might arrive up to a few minutes after, though, even if you're aiming for the original point. [As she talks, Una traces out a rough sort of diagram on the bar counter, using some condensation that has puddled near her water glass.] Deliberately targeting a different point—it can be done. But the margins of error become trickier.