Pauline Hendrika Robinson was on her own and driving a Ford Focus which failed to stop and give way as it came to the junction of West End Road and a 40mph stretch of the B1397 Boston Road, on the outskirts of the village.
There was a "collision at speed" with a VW Golf which was on the main road and was spun round to end up in the opposite carriageway facing the direction of Kirton. Mrs Robinson's car was also rotated, hitting a tree and coming to rest in a dyke.
The 84-year-old, of Bowgate, Gosberton, suffered multiple internal injuries and was airlifted to Queen's Medical Centre in Nottingham. She died two days later, on May 7 this year.
A resumed inquest into her death, held at Boston Coroner's Court on Wednesday (Nov 21), heard that the Golf occupants were Barry and Susan Saunby and their young granddaughter who were heading to Boston swimming pool, having left home nearby at about 8.30am. All three suffered cuts and bruising and Mrs Saunby broke a bone in a wrist.
In written evidence, Mr Saunby said: "As I approached the crossroads I could see both junction entrances were clear of any vehicles and I intended to go straight on.
"Suddenly, I was aware of a silver grey Ford Focus cross from the left. It appeared to be gathering pace but I can't be sure and I don't know how fast it was going. It appeared as if it was going straight over without stopping. I would guess I was about ten yards from the car as it came out. It happened so fast I had no time to steer away or brake or try to avoid hitting the car. It was so close. I didn't see the Focus try to brake or swerve either."
Mrs Saunby, who was sitting in the nearside rear seat, did not see what happened as she was delving in her handbag which was by her feet.
Collision investigators found no material faults with either vehicle.
One of Mrs Robinson's two daughters told the hearing that she saw her mother in hospital the following day and she showed no signs of having suffered a stroke.
Joanne Robinson said: "Her actual words were 'why did I take the scenic route?' So I do believe she would have left Tesco and Oldrids and double-backed and taken that back road through to Kirton.
"I asked her what she remembered. She didn't remember the accident itself. She said 'I was coming home, the shopping's in the boot of the car.' She did say I didn't see anybody coming."
Miss Robinson said her "totally selfless" mother was in agony but was concerned that she wouldn't be able to fulfil her role as organist at a service at Gosberton Methodist Chapel that afternoon.
Describing her mother as the "backbone of the family, the heart of the family", she added: "Even at 84, she would cook, she would plate dinners up for the wives."
Recording a conclusion of road traffic collision, senior coroner for Lincolnshire, Timothy Brennand, said: "We shall never know with clarity and full definition as to what exactly happened. The reason for that is one of the participants in the collision is sadly and tragically not before us to answer the questions that might arise."