Still using a random word generator!
Private
"You can't be serious."
"He checks out. Contact tracing, in my experience, is a remarkable thing when done correctly. You should know that. After all, you ran it on your end."
"But we can't just promote someone for no apparent reason!"
"I thought I had leeway to do what needs to be done." I honestly don't know how he made it through boot camp.
"Within reason."
"Reason dictates this is what's best for our unit, morale, and cohesion."
Silence.
"Are you there?"
"Wait."
Ten minutes later…
"You win; a promotion has been authorized. Your new man is now Corporal Parts."
I briefly researched the term contact tracing. Found uses going back to the 1920's (probably earlier). I'm sure London use contact tracing to help vet new prisoners. The other term-I found history of that going back to the 1600's.