Franklin Regional High School near Pittsburgh
04/09/2014 at 01:00 PM EDT
Hashtag this Instagram post: #lifesaver.
Nate Scimio, praised
for pulling the fire alarm during the Pennsylvania school stabbing spree
, posted a selfie
from the hospital Wednesday wearing a hospital gown and pointing to his apparently injured arm wrapped in gauze.
"Chillin at Children's," he captioned the snapshot.
Scimio's picture quickly was flooded with comments from well-wishers.
"People never know how they will react when something like this happens. You hope you have the courage to help others," user toottoot4 wrote. "God bless you, your bravery saved lives today."
Police took a male sophomore into custody Wednesday morning after he allegedly went on a rampage at Franklin Regional High School in Murrysville, Pa., leaving an estimated 20 people injured.