Some quotes from their forum, ( https://millwall-forum.vitalfootball.co.uk/threads/lower-tier.34311/ if you can stomach it):
"I seem to remember that they gave Brighton the upper and lower tier last time we played. Be a shame if they dont get the lower this time.Proper cup atmosphere"
"If...
Very good. Maybe they could remove the seats from the lower tier and turn the whole area into something more in keeping with their reputation, such as a giant ball pit for the kids #familycluboftheyear