Too harsh
The trio of Lex, Aoi and the princess ran for quite a while before they finally approached the heirs quarters. Before closing in, the princess stopped and fixed her clothes and appearance and turned to glance at Aoi. That's when she noticed that Lex was there as well.
"What are you doing here?" she asked, startled at the sight of him.
"Didn't you ask me to follow you before you started running?" Lex responded innocently. At the same time, he looked around. He had prepared a few items which could create decoys of himself for when the princess would eventually be stopped, and he would have had to make a quick getaway. But that never happened.