There is random, and there is random.
Or, more correctly, there is more pseudo-random.
On most modern computers a series of random numbers is actually a long series of numbers that is different only for different seeds. See the random() docs:
If it is important for a sequence of values generated by random() to differ, on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.
Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number, before starting the random sequence.
There is a whole science of increasing the apparent randomness for pseudo-random numbers generating by computers. For cryptography it can be very important to generate strong random sequences.
In the code you show here all we see is the call to random(). This implies that the same series of numbers could be fetched over and over again.