It’s an extension of the Minkowski diagram in my previous post.
Here is a simplified Minkowski diagram in a rest frame composed of a vertical t axis (expressed in units ct so it is dimensionally the same as the x axis) and a horizontal x or space axis.
For a photon travelling at c the world line or path in space time forms a 45⁰ angle with the t and x axis as it undergoes equal displacement in both time and space.
Note the line forms a part of the light cone in the Minkowski diagram.
An event is defined as having a position and time coordinate.
If two events occur on the x-axis then each event is only separated in space, there is no temporal displacement as each event occurs at t=0.
This has important consequences as there is no ordering of the events.
This is not a problem for particles travelling at velocities less than c where the world line forms an angle less than 45⁰ with the time axis.
This is because length contraction and time dilation causes the time and space axes to undergo rotation which is the geometrical version of the Lorentz transformations.
For each observer the degree of rotation depends on the velocity of the observer but if each observer travels at less than c they will always be in time like region where causality is not violated.
If the observers travel faster than light they fall in the space like region where causality is violated.
In this case it is possible to define events purely on the x-axis but as shown there is no temporal displacement or time ordering of events.
In the diagram in the time like shaded region event O definitely comes before event P, outside this region in the space like region one cannot tell if O comes before Q or Q comes before O.
From a physics rather than maths perspective what this is amounts to is that O and Q occur in such rapid “succession” that the time difference is less than the time needed for a light ray to traverse the spatial distance between the events.
So it is possible for an observer travelling faster than light to answer your question before it was even asked.