In regards to the whole debacle with the vents, it wasn't really as stacked against the OTA as it may seem.
Firstly, they got the drop on me, and I rolled for it. Granted, I didn't do the /me properly, but the admins set me straight. Then after, I said I would go down for three turns, having injected myself with adrenaline to perform emergency surgery on myself to get back into the fight. Everything was going in s2rp until for some reason people on my side started shooting in s2k, I was even still doing my /me's but at that point it was a bust for s2rp.
TL;DR - If it was '100 m of cramped space' your bulky ass supersoldiers would not have been able to fit through the crawlspace, and with zero noise no less.
Then after we rolled for agility in crawling to the tunnel.
But before I move onto that point, I would have to stress the fact that the OTA were much wider than we are and bulkier. Crawling through that tunnel for them would have realistically taken like 20 minutes and would have been very noticeable audio wise, but you rolled a nat 20 for noise even though noise isn't based on random chance, and moreso based on what you're wearing and such, which is why we can hear CPs from miles away due to their jackboots and gear, so the OTA should not be an exception to this.
Anyway, back to the aforementioned point, we all rolled for agility to determine who would go first. I rolled the highest, and went through first. Considering how we weren't clad in full body bodyarmor, we could very much get into and through those tunnels much swifter than any OTA could.