"You should know that I'm not that kind of person," Kaiba says indelicately. "I don't know enough about you--"

Which is a lie, given Kaiba's control issues and rigorous background checking of this particular individual.

"--nor do you know anything about me, other than the fact that I'm a vampire, and your boss. What makes you think that 'being held' is in any way appropriate?"

It's rude, and he knows it. But Kaiba's gotten along best by keeping himself separated from distractions and weaknesses. His only blind spot was for his brother. Still...having said that...

"...Don't think I'm not grateful, though. I could have been in trouble without you, and I'm aware that my gratitude has been lacking. I will repay you for it.

And the window."