I've watched it in slow mow from a few angles a few times. It seems to me that Alex had plenty of room on the right side and got taken away from that line visually, stayed on the gas, and changed trajectory.
Looking right how these guys are riding really keeps a rider from seeing anything on their left, even if they're a little in front. Seems like Pecco planned for this and left enough room.
I haven't heard (surprisingly) that Alex could be helping Marc/team periwinkle with a move like that. I wouldn't think that it was true, but you know the media...stay tuned!