The 19-year-old Idol finalist, who hails from Beverly, Mass., north of Boston, played a stunning piano rendition of "I'll Stand By You" by the Pretenders – bringing the judges and audience to their feet in what's been a gut-wrenching week following the attacks at the Boston marathon. (Watch her performance below.)
After the show, Miller told PEOPLE about why she picked this particular song from the year she was born and how her loved ones are doing back east.
"I have lots of family, lots of friends, who ran [the marathon] and were there. So, yeah, it wasn't a great day," she said. "It's so weird, but I wish I could have been there. That's weird saying that, but I just wish I could have been there with my friends and family, and just been with them."
Miller, who also performed "Halo" by Beyoncé on Wednesday, said everyone she knew in Boston was all right, and she was thinking of those less fortunate. "My heart goes out to all the families who are hurting over their loss or those who are injured," she said.
Could she have picked a better song than the Pretenders' 1994 hit? Probably not.
"I just knew when that happened that I wanted to dedicate this song to them," she said. "The words, the lyrics, just went so perfectly with it, so I was just so glad I was able to do that."
Reporting by PATRICK GOMEZ