How to create via sql and detect via ERRORLOG SQL Server 2008 Deadlocks
Here is a link I read awhile back about retrieving deadlock information via extended events.
http://www.sqlservercentral.com/articles/deadlock/65658/

My guess is that if your query is still running then you have blocking not a deadlock.  Are you sure you went back to session 1 and ran the additional update statement?