This guy's also focusing way too much on the phone. If some mobster or gangster-type wanted the OP to divulge information about what's on his e-mail, the phone isn't the only place they can get that info. Most government e-mail systems are on MS Exchange or something similar, and archiving is often required, so a POP configuration is out of the question, right off the bat.
What does that mean? That means that the phone is likely using EAS or IMAP, which means that even if you destroy the phone, the e-mail can still be retrieved at the source. All they need to do is sit the OP down in front of any desktop or laptop and "convince" him to give up his e-mail login and password. No phone required, and there's no "wipe" app on entering a secret password for Exchange.
You can wipe the phone all day long, but it won't erase the e-mails on the server.
On the other hand, if the OP's bosses at the Department of Corrections was worried about this sort of thing, they would probably implement a policy where an employee's e-mail account is disabled, or the password changed, if he goes missing for a certain amount of time. This would mean the OP couldn't log in, and neither could his phone. The e-mail wouldn't be accessible by the bad guys then.
The DoC would probably also be in a better position to decide if the data on his phone was risky enough to warrant a wipe, which they could do remotely from the Exchange server. But chances are, they might want to opt instead to get a warrant and track the phone's location through GPS and alert the right people to mount a rescue. Something they wouldn't be able to do so easily, if the OP went all Panicky Pete and wiped his phone on his own.