You shouldn't say things like that. No matter how strong your feelings are... There's always the possibility of another.
[Finally, Ian looks at him - and from the look in his eyes, it's like Ian's looking at something he's never seen before. Which is... a bit true. He's just realized and accepted some things, over the course of the night, and... Well, when he looked at Souji, he expected that familiar pang of his heart; the feeling of betraying Shiro. That the guilt doesn't come--it's not something he expected, and instead he's faced with the full scope of his feelings. His trust, his appreciation, his caring--it's almost overwhelming, without the guilt to dampen them.]
Thank you, Souji.
[His voice, though quiet, is earnest. Souji might not know what the flowers represent, but that doesn't give the act any less meaningful.]