1) It is part of the challenge of T5s that they do inevitably have a break and kill things. Humans, other droids, they just kill things.
2)During recruitment remove their legs. They'll be incapacitated in a pod and you can recruit them without risk.
3) Once you have recruited a T5 you have two options for minimizing their damage.
--The first is that you create a Hannibal Lector style self contained prison. You load it up with a pod, recreation items, and an advanced research bench with a multianalyzer. From there your T5 spends all their time researching for you.
--The other option is that you upload an existing android over the top of this one's personality.
The second option is preferable, you get all the benefits of the T5 and none of the downsides, but it's also expensive in time and resources. You need expensive implant chips for both droids, antennas, and you generally want to use the skill points function to upgrade the android you are uploading before they get into a more expensive T5 body.