What if engi would be carying a gun that could instantly build level 1 teleporter consuming the same amount of metal (compatible with eureka effect). I think that would be quite balanced since engi loses shotgun, but gains ability to transport teammates fast. But to make it anti-griefing, engi could destroy only both teleporters (entance & exit) at once, not separately. Teleporter could be built within a higher range like up to 10m, like when engi runs from atack he can build teleporter far from him and teleport teammates to help him. And the Tele-portal gun would be working with mouse buttons (one for enter, other for exit)?