Alas, no. Your suggestions would determine that he knew it before he was arrested, none suggest his on-going memory of the password.
It's harder because the other questions only have to look at state of mind for a particular moment in the past before police activity could have influenced it.
This is closer to Heisenberg. The act of questioning can cause the accused to forget. That is exactly why this is a screwed up law.
Have you truly never heard someone say "If you hadn't asked, I could have told you?"
You've never known anyone who can type their password by muscle memory but cannot consciously call it out other than by watching themselves type it?
There are a great many factors that can confound memory and all must be ruled out to eliminate reasonable doubt. Furthermore because memory can be malleable and tricky, even evidence that he later recalled the password isn't evidence that he could recall it when asked. It's actually common for an answer to pop into mind once all pressure to remember has passed.
OTOH, there's really only one reason to arrange to meet someone in an out of the way place and take a gun, gloves, and a body bag with you. The prosecution and the judge don't have to determine what the defendant is thinking NOW.