Well done avoiding a dangerous situation with no-one ending up hurt!
fwiw, I've spent the most part of my life trainig and teaching japanese Ju-jitsu, where there are many techniques for unarmed defense against knives. This has taught me that knives are extremely dangerous! Do not underestimate a knife wielding attacker!
The philipino martial arts are arguably the most developed as to knife defence.
Take a rubber knife, coat it in red chalk powder and get someone to "go crazy" on you. Good luck!