Grouping up with your team is a great way to improve your chances during an Overwatch match, unless you have a Genji that can take out the enemy team all by themselves, like in this clip posted to Reddit.
In the clip posted to Reddit by Sisym, the Genji's team is attacking on Hollywood and it looks like the opposing team is defending pretty well, until the Dragonblade comes out.
You can practically see the panic in the enemy team as they try to position themselves after hearing Genji's ultimate, but all they manage to do is line themselves up to be wiped out.
Even though they technically don't eliminate every player on the other team, thanks to a little help from D.Va, the Genji still takes out five of the six enemy players with his ultimate.
Both teams, Genji included, probably had no idea how this happened given that the defending team seemed to have a good hold on point and there were almost no attacking players around.
Genji players are infamous for not listening to teammates, instead choosing to go off on their own and attempt to get plays like this one.
We don't know whether or not the Genji's team ended up winning this match, but at least they didn't ask for healing during the clip.