Advice for instax mini 9 in unusual lighting locations?

I want to preference this with i know im pushing the limits of capability and it wasnt designed for this kind of photography. But the challange and tinkering is part of the fun!

So I love my instax mini. Its dumb fun and takes great lil shots. One of my favourite places to go is imersive art exhibitions. Were talking places that look like the sets of old science fi shows. A lot of these places have heavy ambience and focus on different coloured lighting. The trouble is, the flash is causing the lighting of the room to be overpowered and the effects to be washed out. Im also finding that its hard to capture the detail even when the flash is on and I go on hi key setting. Anyone done.anything wild? I was thinking maybe some gaffer tape over the flash to see how it handles it.