When Lucas finds out Mark is missing he jumps on his horse but his rifle isn't in the sheath. A moment later Lucas is seen riding his horse and the rifle is now in the sheath.
Near the end, Ben Vargas gets on his horse but Lucas jumps on him and they both fall into the water. When the characters first appear in the water they are both covered in mud and their shirts are very dark. In the next instant Lucas' shirt is wet, but it is white with no mud on it.
The use of the phrase "step on the brakes" by Micah seems out of place. There was a foot brake on some wagons; but this phrase is rarely if ever seen used this way, any where else.