Timing belt

[littleman]

Good day all.
Something strang has happened to my 2005 3.8 v6 petrol Paj. A few weeks back a funny ratteling sound suddenly came from the engine compartment.[sounded similar to small stones being shaken in a tin] On inspection I never saw anything that would identify the problem but it was coming from theair filter area. Then as suddenly as it appeared it disappeared and the engine ran as normal. This weekend I had to use it again and on my way home it started again. I was only 3kms from home so I carried on driving home. I noticed that the powe steering was not working and the battery charge light had come on. On arrival at home I checked undwe the bonnet and found that the timing belt had somehow come loose[not snapped] and I easily removed it. Now my experience with snapped timing belts tells me that the engine should have come to a grinding halt with bent valves etc. but that never happened. It ran smoothly all the way home. Can anyone enlighten me as to what could be the cause of this.
Many thanks