Get one of those cheap eyeglass repair screwdrivers. In my experience it's small enough -- and tough enough -- to do the job.
Doesn't matter if you mangle the release lever as long as you manage to disconnect the socket without mangling the wires; you're not going to reuse it anyway.
But I'd go with what Thinkgood says. Cut close to the wire entry hole and re-strip the wire properly, that way you are sure you start with a new piece of un-nicked wire. Sometimes that "blade" that holds the wire in place tends to score it a bit.
