Sie wurde über die Köpfe ihrer Vorgesetzten hinweg befördert.

I think “superiors” might be a better translation of “Vorgesetzten” here; it is currently translated “seniors” but in English the word “seniors” usually means older and does not necessarily mean higher in position in a workplace (it CAN mean this but not necessarily), whereas “superiors” necessarily means that the people are in a higher position in the workplace hierarchy, and I’m pretty sure that’s what this German sentence means, i.e. it is not referring to age.