Because of the free draggables ... Spoiler: How I won I didn't move B at all and just dragged the free platform over the win. Which probably wasn't what you intended ... Spoiler: So I also did this Used the platform as a bridge for B to avoid the Zappers and reach the win. But doing so took a couple of tries because it kept floating over the win even though that was not what I was trying to do.
Assuming you do not use moving parts to win I do not understand how the yellow robot could reach the red box. I also tried to suicide B and then crush him to launch him.
@Battle ship - It would appear at first that you did not test your level prior to uploading it; am I correct? As the others have mentioned, I also believe that the only way to win is to perform some unseemly steps. Could you please check and get back to us?