"Cannot continue the execution because the session is in the kill state" when querying system tables
It's possible there is corruption in those system tables.  Try running:
DBCC CHECKDB('YourDatabaseName') WITH NO_INFOMSGS, ALL_ERRORMSGS;

On all the databases on this instance to check for corruption.
It's also possible you're encountering a SQL Server bug. Try checking the SQL Server error log for any error messages around the time you get that &quot;a severe error occurred&quot; error message.  You might get more details about the error, or maybe even stack dumps that are happening at that time.