A man suffered a “medical episode” behind the wheel at Warwick Hospital car park in what caused damage to several vehicles and a wall.
Emergency services were left “stunned” by the collision outside the A&E department on Wednesday afternoon.
A middle-aged driver lost control of his Land Rover, colliding with a van and forcing another car onto the bonnet of a fourth vehicle.
An ambulance crew already at the Lakin Road site rushed over to find the man still in his car after crashing into a white van and red Seat.
After being freed with the help of firefighters, the patient was immediately taken inside the hospital for treatment.
Nobody else was hurt in the collision which saw the Seat forced forwards, through a small wall and onto the bonnet of a silver BMW X5.
A police spokesperson described “slight injuries” at the scene just after 4.20pm on Wednesday.
A West Midlands Ambulance spokesperson said: “Ambulance, fire and hospital staff were left stunned after they responded to reports of a crash in a hospital car park.
“When crews arrived they found a middle aged man in a 4×4 Land Rover who had appeared to have suffered a medical episode at the wheel.
“The driver of the Land Rover was assisted out of the vehicle by ambulance crews and assessed before being taken into the hospital for further tests.
“Thankfully no-one else was injured in the crash.”
A Warwickshire Fire and Rescue spokesperson said: “One car had mounted a wall and had hit other vehicles.
“One person was trapped and upon arrival, fire fighters used small gear to release the trapped casualty.
“Fire crews were in attendance for approximately 40 minutes.”