When someone walks in on a murder, they tend to freak out just the slightest largest bit. "Oh my GOD, you KILLED him/her!" "What did you DO?" "I swear I won't tell ANYONE, just don't hurt ME!" So on so forth…
Police get involved, crime scenes are established, neighbors that earlier had good opinions of the supposed murderer and victim come to the sudden realization that there always was something fishy about those rascals…
The witness could meet a possible death at the hands of the murderer or testify against the murderer come the trial. All in all, it's a messy, traumatizing business and no one really enjoys being the witness. At the same time, it's plausible the victim doesn't like being the victim either. The only person likely to enjoy their role, if only the slightest bit for the slight rush, is the murderer.
Rock Lee unlocks the door to his apartment and skitters in with an armload of groceries and a flushed face, courtesy of Mr. Winter who decided to come visit a month late.
Animalistic cries of torture echo from the small exercise room he has, followed loudly and awkwardly by the thumping of having something heavy impact with the walls.
Rock Lee immediately goes into action!
That is, if action includes patiently putting all the groceries away, all five bags of fruits, vegetables, spices, dairy products, and ramen. And then just as casually beginning supper and sipping a health drink all the while.
The screeches and groans of pain and passion continue.
Lee carefully waits it out for say… another ten minutes. And then someone decides to knock over his weight set. And he knows someone knocked it over because the floor quakes and he hears the neighbor beneath his apartment screaming like a banshee. She most likely has a new set of weights conspicuously in her living room, plus a scattering of rubble. Lee will have to talk with his insurance company again to see if they cover that.
"That is enough!" And he charges, because this is him going into ACTION, not just action, and forces his way into the demolished and pitiful-looking home gym.
Uchiha Sasuke looks innocently up at him, as if he doesn't even see the wreckage, and continues to force feed his nemesis, one Uzumaki Naruto, a long, thick rod.
"Sasuke-san! Not. My. DUMBBELLS!"