once the boot is torn it has exposed the internal joints to sand and dirt ect wich can make them weak and beak, spitting out the remaining half of the Prop shaft spinning into your tranny, the bottom of the seat, possibly thousands of Dollars in damadge, the Prop shaft loop prevents the shaft from coming loose if it fails therefore saving your tranny and undercarrage
if your concerend about the ride home and I would be, just remove the prop shaft (8) bolts on hex head wrenches and drive home in 2wd .very fun buy a camera for the smoke show