pipelining within channel 0

So RFC 3080 says:

   A BEEP peer acting in the server role must process all "MSG" messages
   for a given channel in the same order as they are received.  As a
   consequence, the BEEP peer must generate replies in the same order as
   the corresponding "MSG" messages are received on a given channel.

For channel 0, which peer is considered "acting in the server role"? 
 Cannot the modifier 'acting in the server role' be taken away?  I'm 
wondering if the chan0 MSG messages need to be replied in the same order 
they are received.  Specifically, if peer A receives <close number='1'> 
then <close number='2'>, but it takes longer to close channel 1 than it 
takes to close channel 2, cannot peer A reply to the 2nd close message 
first?

Thanks,
Lei