Excellent video. What would be even more powerful is if they repeated the experiment, but with the 1000x agar right next to the antibiotic-free medium to illustrate what happens when antibiotics are used properly.
In a properly-applied therapeutic situation, there is no such safe haven, and one hopes that the subject's immune system would be able to exterminate the much smaller load once the antibiotic's done its job, instead of leaving any stragglers behind to develop resistance.