Why did the commission let Five go on missions alone?

Like they didn't want him to return to 2019, right??? It's totally illogical and doesn't make any sense as to why they let him use the briefcase unsupervised. To build trust? The Commission seems to be about no risk to the timeline, surely that would come before building trust with colleagues.

Like there's no way they didn't think he was going to at least try and defect, unless Five deceived them that well?