I didnt understand that video or what he did but I think did something like that before, but I did a funnier one one time it was a team slayer game and three of the guys went to the grav lift and jumped over at the same time then on the other side I through a power drain on the grav lift which blocked the first from getting over to the other side then which blocked the second guy which blocked third guy and all of them fell to thier death . It was hilarious but then the fourth guy killed with a plasma when I jumped on the grav lift
u can throw anything off the cannon. but to have some fun put two gravlifts under each cannon. set it so that an object goes off the man cannon then hits a gravlift. it will then bounce to the next then up that one into the cannon so that it makes a never ending cycle. in forge get on a turret and have a friend put u in the cannon u will bonce around.