Fair enough. I used to think it was bogus too. Everyone has their own energy signature. With time and a lot of practice, you can get an insight of the sort of person you're dealing with.
That's...problematic. I can understand why you're reticent for him to join. I only know what I saw, and it lead me to believe he's a man who has many regrets.
Considering it's a mission for another man who has many regrets, I'll have to leave it to your best judgment on if you want Mr. Rumlow to join.