Regarding the part of the question involving booting into Windows without drivers without having to provide the Bitlocker recovery key, I can share the following experience (if it helps any future readers):
I work on a Windows 10 machine that has Bitlocker installed. I have been able to enter "Safe Mode" without entering the Bitlocker recovery key. I did however, have to enter the Bitlocker PIN (6 digit number). It sounds like the original poster knows the PIN (otherwise how did he/she login to Windows to install the audio driver?) but if someone else reads this and does not know the PIN or the recovery key, then sorry, I can't help you.
Microsoft has web pages and community forum topics with information on entering Safe Mode with Bitlocker installed, but everything I read said to press F8 repeatedly before Bitlocker launches. In my case, I have a USB keyboard with Windows drivers and the OS is on a super-fast SSD, so the number of times I have successfully pressed F8 repeatedly between when the keyboard lights up and when the Bitlocker screen suddenly appears has been 0/10 attempts. Someone with a keyboard connected to a PS/2 keyboard port might do better.
However, you can also use the "System Configuration App" to set the machine to always boot into Safe Mode (on the boot) tab. It is necessary to come back later and switch this back or else you will continue to always boot into safe mode.
Once you have made the boot setting change using System Configuration app and rebooted, Bitlocker will provide options to enter the account recovery key or to just enter the pin. Entering the pin should get you into Safe Mode. That's what I did. Once you have done whatever you were going to do in safe mode, go back to System Configuration app and change the boot options.
