The 25th Anniversary DVD did not have the mono option. I’ll have to do some cross checking but I never noticed a drop in volume in that section on the mono on the 30th Anniversary DVD (that’s personally my go to version for the mono). Below are some clips. Based on what I’ve listened to over the years on various releases I’m pretty sure this is the source of these tracks.
Laserdisc
30th Anniversary DVD
Blu-ray
One thing I don’t really like about the LD track in this instance is the gun shot when he says ‘bitch’ lacks the punch it has in the other two examples. Just my personal opinion over what’s the best version of the mono, the LD version is a bit more definitive while IMO the track on the 30th Anniversary DVD is a bit more crisper though it has some audio issues in some spots such as audio crackle during the cage attack scene (an issue that also plagues the Blu-ray mono).