All the time I have been on Quantum and thats a lot of times the ride op has never said scream if you want to go faster. Not sure if they can make her faster depends on the setting I think not sure.
For most of the staff it was there first day working at Chessington so they were nervous so they are bound to be a bit quiet and dont say much. That is what I think anyway.
Yes, someone on here said if 25% of the themeing is not working the ride will be closed and the themeing will be fixed it is part of the contract. But if it's just the blades then it should be open.