Firefighters were called to the newly opened Cineworld at The Beacon on Sunday evening after a power cut caused problems.
A spokesperson at East Sussex Fire and Rescue Service said crews from Eastbourne were scrambled at 8.40pm to a report of people shut in a lift.
Four people had to be rescued.
Visitors said the cinema suffered a power cut and more than 300 people had to be evacuated.
No further details have been forthcoming from Cineworld as yet.
Photo by Robert Findon.