Great, I'm not going insane and making things up, haha, others see it too!
Out of all the songs I have listened to and analyzed, the few that stand out as the closest in relation are either "On That Day Five Years Ago", or "Holding My Thoughts In My Heart". Neither comes across perfectly, but there are logical reasons for both being in that part of the movie, so who knows....heh, nice intriguing problem, though! ^_^
****edit****
Went back and listened to "Water" and "On That Day..." back-to-back, back and forth, and I am 95% positive that it is that one. At about 0:52 and 2:29 in "On That Day...", there is that few-note succession that sounds almost identical to the part of "Water" at 1:50 and 2:03. So yeah, I think that has to be it.
Do I obsess too much? ^_0