This was not supposed to happen. While Death's power of compulsion evidently did work, it didn't seem to last for very long. Using it again to get rid of Larxene wouldn't work - she was expecting it now.

He saw the lightening spark and hit Flonne with dismay that quickly turned to anger. This would not happen. Not in front of him.

Timon's plea was unneeded, as Death was already moving to attack. Swiftly reversing his grip on his scythe, he swung the butt hard at Larxene. There was no way he could use the blade right now: in such a crowded place, he may inadvertantly kill somebody were the blade to be employed.