Eula takes herself very seriously. She holds herself in very high esteeem- such is the lot of a knight. Amber, on the other hand, is somewhat easygoing. She is often the first to reach out to new recruits and make friends, lend a helping hand, what have you.
Unfortunately for her, when she extended this kindness to Eula, she took it a bit the wrong way. Eula saw this almost as an insult: Did Amber not think her capable? Did she think that a Spindrift Knight needed someone to carry her bags? That she NEEDED the help?
Clearly, the record must be set straight before this new reputation disseminates through the camp. A show of superiority was in order.