The firewall between adjecent transformers are made to prevent the other transformer from damage when one is going to catch fire or blast.If the distance between the transformers is as per guidlines of Standard code then sometimes there is no need of firewall.The safety of the person is other...
Just to get the understanding of the inrush phenomenon see the link:
http://www.allaboutcircuits.com/vol_2/chpt_9/12.html
The page explains the inrush phenomenon beautifully.