Those who are interested can check out the footage taken by the player below.
When someone in the comments stated that they wanted to replicate it, the OP said, "Good luck! It's the best part of playing Lucio honestly. I recommend looking for a wallride guide on YouTube, [because] there are quite a lot of moving parts here..."
Incredibly Clean Lucio Rollout into Triple Environmental Kill
Unfortunately for those players, they are immediately knocked off due to the timing of it all. In the comments, people speculate that the enemy Lucio speedboosted right out of spawn and doomed those members of his team.
When asked by another player how to mimic something like this, U/Purple_Jay wrote, "If you seriously wanna try going for these... the basics are that you wanna jump off walls as soon as you land on them to build speed and looking up or down actually has an impact on how far you go. [In the clip,] you can see I look up on the first few wallrides to get a bit of extra height."