Well, since the monster is normally used to dodging every single attack, his body is built to grab, kill, then move on. Also, I'm blaming it on the fact he's four dimensional, so maybe his body structure isn't very good. When he charged Naoto, he expected him to side-step so he could grab him with his arms. Hint as to why he freaked out when people started lunging at him. Or, where shoved by Kassy... xD