Maybe make the last clause (kono mentsu) more reflective of concern than of holding him back, since the intended message (if Asa is correct) is that Aerith and Red XIII are first and foremost people Barrett wants to
protect rather than fellow fighters. The interpretation makes you wonder if the elevator boss was added late in development.
"Sh*t! We're completely surrounded. On my own, this'd be nothin'... but these guys...wonder if they'd make it...?"
EDIT: I did a quick search for the Mahjong term. This is what it appears to mean specifically in that context, which is pretty clearly where the metaphor is drawn from (
http://www.osamuko.com/2009/04/03/big-list-of-japanese-mahjong-terminology/):
mentsu -- meld -- [the term used here] "meld" comes from [the Western card game] rummy
A "meld" is when you have, say, 3 5s and may play them to earn points. I'd never known the formal English term. So the metaphor may be that the pair [Aerith/Red XIII] share a certain characteristic [needing protection]. It might make the gaming metaphor is little clearer, if it wasn't before.
I don't know if there's a way to work in a gaming metaphor without making the tone seem weird in English (this is probably a pretty casual expression in Japanese, but in English the equivalents will make him sound like Setzer), but it may be worth thinking about.