Tried to follow my tanks suicidal charge forward. He got focused down pretty fast and I ended up in a building behind the enemy lines with no friendly players close enough to fly to.
Decided to bum rush the enemy from behind instead of sneaking back to my own team and so I climbed up the stairs and out onto the walkway on the buildings upper level. That way I managed to catch their Mercy while she was healing a almost dead Widowmaker, and a few pewpews later the WM is dead, Mercy fights back and a second later she joins the WM on the ground.
Jumping down from the walkway and onto the street I land behind their Soldier who also dies to my pewpew of doom.
Turn around, back into the building, through some rooms and up the stairs again, and suddenly I'm behind a Bastion. I'm shooting the core on its back and instead of turning around and shooting me he tries to repair himself. A second magazine to the core and a punch later I get my 4th kill.
Had a short range duel with a Zenyatta whose aim was so bad he couldn't hit a barn while being inside it (killed him, too), then going outside again I'm facing a D.Va. Fearing that I won't survive a short range slugging match with
that thing I flee back towards my teams spawn. Almost dead I finally see a friendly Tracer and shift-fly towards her, D.Va follows with her boosters and gets blindsided by a friendly McCree who promtly kills her with a stun grenade + fan the hammer.
And this is how a Mercy causes a team kill on Numbani.
Overwatch