This is only possible while playing co-op and online. Because of lag your co-op partner will always appear a half-step behind where they are actually placed on there own screen. This allows for both players to be running in front of there partner on there own screen. Its actually easy to set up, and almost all co-op runners boost on accident in there runs somewhere, unknowingly saving time. The very first checkpoint of the game is a perfect example. I believe every co-op run of mine features a boost at the start of 1-1. NG+ Co-op PC Normal record should have both me and Snow's POV of us boosting. Hope this is helpful