How did Boc get into the Academy?

If you give Boc a larval tear, he goes and gets rebirthed by Rennala.

But how?

The Academy is protected by a barrier that requires a key, that has never been used, to get inside. Sellen and Jerren make sense, they have the connections to get a key if they already didn't have one.

Boc on the other hand shouldn't be able to get inside the academy so how did he? Its not like the keys are just lying around.