Wait ---- your dad still has rule over you? Of course you can drive yourself and leave when you need to!!!! That's only good self-care IMO. You have permission to do that... you can give yourself permission to do that!

If you can't find the strength to leave early, then do take the book, and politely excuse yourself saying, I have a test I simply must study for... so I'll be in the xxx room reading and studying if that's ok???? And go read. Anyone who doesn't understand...well, they won't understand even if you draw them pictures I think

Go have some fun and leave. You are your own person.