BitLocker is crazy easy to bypass if you have physical access to the device. I work IT, and had to demonstrate to our head of security, that if you just pop in a Linux USB and boot from it, the drive is completely open.
This sounds like BitLocker wasn't enabled on the drive. All of the laptops I've deployed with BitLocker are very good at detecting tampering and will immediately go into lockdown mode. A Linux USB most likely requires Secure Boot to be turned off to boot, if so, the TPM tamper will trigger and BitLocker will require the recovery key at next boot.
-- Harsh. But extreamly funny. Interesting that it sees my 5800X3D as a 2-core processor. Turning off DDG privacy essentials yeilds the correct core count, etc.