Why Does This Deadlock?

Using SQL Server 2000 SP3a, I run the following in 2 query analizer
windows on the Northwind database, the second one always gets the
deadlock Msg 1205:

Window 1:

declare @cnt int
select @cnt = 5
while @cnt > 0
begin
begin transaction
select * from orders (updlock) where employeeid = 1
update orders set employeeid = 1 where employeeid = 1
waitfor delay '00:00:03'
commit
select @cnt = @cnt -1
end

Window 2:

declare @cnt int
select @cnt = 5
while @cnt > 0
begin
begin transaction
select * from orders (updlock) where employeeid = 1 and customerid =
'ERNSH'
waitfor delay '00:00:02'
commit
select @cnt = @cnt -1
end


The query in the first window gets 123 rows and places update locks on
them, then updates them and commits. The query in the second window
gets a subset (about 5) of the results that window 1 gets also trying
to place update locks on the same rows. Shouldn't the query in window 2
just wait for the transaction in window 1 to finish? why would it
deadlock?

you can also get rid of the delay in the second window and it will
deadlock faster.

thanks in advance.
Eugene