ETA: at some time in the fic, JARVIS specifically recalls the Obie-pulling-the-reactor scene in the living room as his reason for being more proactive in his protection.
I really love protective!JARVIS, and would be v.v.thankful if anyone can identify this fanfic.
Son of ETA: I can't believe I stumbled upon it accidentally! It was the third story in icarus_chained's Tony and Bruce series (AO3 link). I love, love, LOVE this series!