Drew jerked his carbine from its saddle boot, saw Anse beat him to that action by a scant second or two.
Drew simply stood there, staring at Anse riding away into the sunset. 
mnli hypothesis: Drew simply stood there, staring at Anse riding away into the sunset.  premise: Drew jerked his carbine from its saddle boot, saw Anse beat him to that action by a scant second or two.