Learned this the hard way, the tek spears do friendly fire so if theres multiple of you attack her one at a time, i did this with 2 others and they both died to friendly fire in just a few swings so i was left solo, be careful it can 2 swing kill your friends

When she points a single scythe at a player use the deflect with the tek spear or the attack will do loads of damage and sometimes one shot you even at 1000 hp on your player.