[Twisted-Python] re-entrancy question

[apocalypznow]

I've got a Twisted server application that also listens for other types 
of TCP connections on another port.  Upon receiving certain data on that 
other port, I make calls to objects subclassed from pb.Avatar.  Given 
that Twisted runs on one loop doing select(), I think I have a 
re-entrancy situation.  Is this:
1) dangerous?
2) why is it dangerous?
3) and how would I go about achieving what I want safely?