This feature has already been discussed with some customers. The problem is that it defeats the purpose of rules - if an admin wants to block certain type of files then why give users an easy way to "smuggle" these files into your company (e.g. just put it in a DOC file)?
The problem with *.tmp can be solved easily, but if we find a good use case for "Is in a container" setting we will certainly implement it.
You can remove the *.tmp extension from the rule. We already removed it in newer versions because it caused this problem.
You can see Office documents blocked because they are archives and some of them may contain *.tmp files (rules are evaluated on each file in archive).