CalebK2

The entire time Vin was searching for the spy, I kept thinking she would Duralumin soothe each of the suspected crew members to see if they were affected. She didn't know yet that duralumin soothing would take control of a Kandra, but it certainly would have easily let her tell if the crew members were affected by allomancy or not since they would have been visibly affected if it could have affected them. She could even have warned each of them what was going and that she was about to do it as a test. If they agreed to it, then they were clear. If they refused to do it, then she would have known something was wrong. The only reason I can see that she didn't do a test like this was because like RYANHOME says, she just really doesn't want to confront the possibility of her friend being the spy. When she suspected Demoux and she was following him, I kept wishing she would just duralumin soothe him while he was in a dark alley and been done with it.