We don't exactly know what system they use. It's clearly d20 based, but that's about it.
There are systems where the dodge roll reduces the attack roll. A -2 on the attack roll that turns a 14 into a 12, when a 13 was the target number would be enough to dodge.
The 15, 19 and 14 likewise could have reduced the attack roll below the minimum threshold and turned them into crit failures.