Lol it's part of his gear, they're like... here. The blade attaches to the triggers that control the cables and gas, and they're made like boxcutters to maintain sharpness and also to be easy to break off in segments in case the tip becomes dull or gets stuck in titanflesh. Those giant sheathes they wear on their hips carry a whole bunch of replacements, just in case.

He just doesn't feel comfortable in a new situation without them. :|