You got lucky. Ease outs are good for one thing. Breaking off and making the problem worse. As they screw in, they expand the broken fastener and usually lock it down, causing the ease out to break. You talk about a hell of a time when that happens.
Well I guess I must be lucky because I've used them twice and they worked both times. Admittedly the engine was recently rebuilt so the bolts hadn't been in there for 40 years but they still worked.