You will need a bright light. You can use the night mode, but the colour contrast isn't great, and the picture is worse. Even with good lighting ,the quality of Nokia videos isn't great as although it may be a 1.3 million pixel camera for example, the video is in lower resolution (at least on my phone). Also don't move the camera too quickly, as the video will be jerky.
By the way I haven't tested my camera in a cave, just in similar dark and hostile venues: the inside of nightclubs!