Marr and Beniko were also receiving amps, doesn't really matter. Plus during the fight, Shan uses BM.
Neph trying to minimize the feat by claiming nexus is easily the greatest double-standard ever unleashed.
The large temples that contained a lot of the energy for Vitiate to return were all destroyed in bombing runs.
And nah, Revan uses Force Teleportation on the Foundry cutscene as well, so no, not game mechanics at all.