The Nimrods have the ability to counter any mutant powers after engaging them in combat after awhile. In Namor's case they started to take mess with the humidity to dry him out . I was actually impressed with Colossus though about half a dozen Nimrods saw him as the biggest threat at that location and had to hold him down together as they figured out a way get passed his durability and strength. They did manage to break his arm but the fact that it toke half a dozen of them were as just one Nimrod is slaughtering others is rather impressive, it toke the threat of an Omega Level mutant to get them to ignore Colossus even after they broke his arm.
They say something about his strength being 1.5 tons for every pound and compensated for it so does that mean his durability is some how linked to his strength level? and if so and he can withstand blows from adamantium then I wonder how Logan's bones would fare haha. Seems the Nimrods can increase their strength if they had to go over whatever 1.5 tons x (insert colossus' current weight) is in strength.