When faced with the decision, arrest or kill, the obvious tactical decision is to kill. An arrest allows the opponent to continue speaking, takes longer, and may render the arresting party out of position. Arresting provides little tactical advantage to the arresting party.
If however, interacting with an arrested enemy allowed an individual to listen in on the communication of the opposing team, an arrest could provide valuable intel.
For example, say a guard arrests an intruder. He may now listen in on the intruder comms. However, he may leave himself or his teammates exposed as he listens, for he would not be able to listen to both teams simultaneously.
Another idea would be to allow the arresting party to communicate with the enemy team. This would allow for a more dynamic variation of the above suggestion.
For example, say a guard arrests an intruder. He may now listen to their comms. The guard may try to thwart suspicions of the enemy team. He may lead his opponents to their doom. He may plant false information within the intruder ranks. As above, he may leave himself or his teammates exposed, for he would not be able to communicate with both teams simultaneously.
It may also be beneficial to allow an arrested party to be freed by their teammates. Although this may tip the scale in favor of killing rather than arresting, it could balance out any issues that may be packaged with some of my prior suggestions.
My final suggestion is the capacity to drag bodies. Dragging bodies could refine gameplay into that of a higher tier stealth game. Whether it be a teammate or an enemy, starving the opponent of that valuable intel can be an integral part of stealth gameplay.
Thanks for reading through my ideas, I welcome any and all criticism with open arms. Thanks in advance for your feedback.