Someone recently posted worrying about being seen as overqualified when trying to enter a new career direction, because they have an advanced degree in another field.
This leads me to wonder: Could one perhaps get away with just not mentioning the advanced degree? Most of us (not all) do get a more basic degree first, so claiming only a BS is misleading but not actually lying. And if you got the degrees at different schools (common in some fields), a basic check would be unlikely to expose this omission.
It does require that you explain what you've been doing in the meantime, but it might be possible to say you've been working in your second field without having to admit to having earned the degree. If you've been doing programming for bio research, that's still programming experience, for example.
And of course it's likely to come out at some point. Hopefully after you have made yourself invaluable...
Feel free to close this as speculative/opinion/underspecified/discussion. It's half an idea, and half an hour from now I may find I'm being a halfwit.