iirc, when I did testing on this if you both jail the same, then one (I can't remember which) can't do anything except end the meeting and the other jails as normal and is allowed to kill/talk with the suspect who can talk to them. I may have confused myself tho and could be wrong. Regarding both jailing each other, Sikrul is right.
in the event of both jailing same, neither can see the other's messages.
if both jail same suspect, suspect receives messages form both and if either no-kills the nokill overrides the other's kill.
when jailing each other, both go into a meeting where neither can kill but can only end meeting.