Booting window 10 off a different when one drive is bit locker encrypted

I am trying to correct a problem created after a customer's IT pushed a security package including bitlocker on the OS drive to a embedded PC on a piece of mission critical hardware.

Our software is completely crippled after they secured the PC. Since the PC has bespoke hardware so replacing it has a long lead time. The system has second drive with a bootable copy of windows on it. ( it's a mission critical system ... we included redundancies. )

Normally I would have the end user boot off the redundant drive. However I am unsure how bit locker would react, would it trigger bit locker to lock out the current boot drive?

Are their steps that I can take to prevent data loss?

Most importantly would I be able to boot back from the current OS if required?