1998 520 I Problem

[PARKREG]

I Parked The Car Locked And Armed The Doors With The Remote On The Key. When I Returned 30 Mins Later And Pressed The Key To Unlock The Alarms Went Of And The Doors Would Not Open. Also All The Electrics Seemed Dead.i Called Out The Local Recovery Firm Who Could Not Open Up The Car. So The Said They Would Have To Tow Me To Their Garage. However As They Jacked Up The Rear End Ready For Towing, My Hazard Warning Lights Started Flashing!! And I Found That The Doors Would Now Open Using The Key Fob Remote !! I Got In The Car , Started Up No Problem And Drove Away, Any Ideas What Could Have Caused My Problem ??