In this clip one can see Jessica 'feint' with an Advancing Foot Sweep which her opponent responds to by withdrawing her foot (her left). This has the consequence of momentarily putting her off-balance and before she can correct this Jessica seizes the opportunity and turns in for her signature throw.
This is a very successful move for Jessica but works as a result of the time and effort expended in Uchi Komi (turning in and out practice) as well as fine tuning in Randori.
It is of course possible that the foot sweep may work as a throw in its own right and as such, the feint must be 'real'. If the foot is not removed, the opponent is thrown with the foot sweep, but if it is, then the shoulder throw comes into play. The key is in the timing.
As a further development, if the opponent responds quickly enough to correct her balance and thereby block the shoulder throw, it is almost certain that she will be off-balance to the rear and in that event, Jessica would immediately switch to O Uchi Gari.
Through this routine (and the others that precede and succeed, one develops the concept of 'continuous attack' in the expectation that however good ones opponent is, sooner or later they will be caught out if ones technique is good enough.
For these reasons it is also important to enter Judo with a good 'spirit' where one is not afraid of losing, because in each event, win or lose, there is something to learn and to take forward.