You're no longer on Earth, and the circumstances have changed. No offense, but the track record for this kind of thing isn't good enough to merit the trust you seem to be expecting. You're also assuming that the civilians will calmly stay away from you and your conflict, which is demonstrably not the case, or they wouldn't be on board at all.

If you're not going to get rid of the Yeerk, then decide what you are planning to do with it. If you are, then kill it and don't be stupid.

Given the fate of the last intelligence to cross the line of squeamishness and vengeance for this crew, I doubt highly that death is the least favorable option.