@Guroga: Given the whole monitor system, it wouldn't be long until he is shown doing it anyway, and he already plan to conquer the dungeon so he'll have to fight that dragon at some point.
She did panic'd a little upon learning that Tsutomu is actually 22 years old, that all the clinging she did to him, now that she realized he's a proper adult, might be....'bad'
Btw Amy is ~18 and Garm is ~20 since he didn't remember much of his childhood.