He had all these brilliant ideas about how he'd bury it.

I shot every single one down, not because they weren't technically feasible, but they were a directly fire-able offense.

When done, I detailed the politics of the issues (and the people 3 levels above him), and he came to the rational conclusion to take the year to build skills in anything he can, as long as it is either interesting or marketable. Things that interest him can be on "own time" at home, but the company owns his ass while he's there, and C# is marketable, and you can always blame MS when something fails.

He needs to recruit a 2nd that they trust to fill in for him if he wants
to write in perl. And then he goes through channels. But he buries NO
code. That's the evil programmer mentality, and I'd stop training him
if he develops it. Too limiting a world-view.