throw off vs throw under the bus

To expel, reject, or renounce. 

To give forth in an unpremeditated manner. 

Of a horse, to eject its rider. 

To introduce errors or inaccuracies; to skew. 

To confuse; especially, to lose a pursuer. 

To discard or disown. 

To betray or blame (something or someone), as a scapegoat or otherwise for personal gain.