Ger says that Kat has a tendency to push things to extremes, to go over the edge, merely from a juvenile desire to shock, which is hardly a substitute for wit. One of these days, he says, she will go way too far. Too far for him, is what he means.
Ger observes that Kat often takes her actions to the extreme, motivated more by a childish urge to provoke than by genuine cleverness. He implies that this behavior lacks the depth of true humor, suggesting it is more about seeking attention than showcasing wit.
He warns that if Kat continues down this path of pushing boundaries, she risks crossing a line that may alienate him. Ger's reflections convey a sense of concern for the consequences of her actions, indicating that her penchant for shock could have serious implications for their relationship.