I really did have an awesome Turian Sentinel TECH ARMOR! moment once.
Way back early in my ME3 MP days, was doing a Silver PUG and got Cerberus/Reactor. Had a Vorcha teammate (don't remember the other two) and we kinda stuck close to each other. I had experienced success recently in saving my own life from Phantom's by detonating my tech armor, so I was feeling rather confident about it.
He and I are working on a Phantom, whittling her barrier down with our guns. I then see her do her little initial melee sword hit on the Vorcha and heard the sword striking his armor. I knew the sync-kill was coming next. I was fast enough and close enough to immediately close the distance and detonate my tech armor right next to the pair, killing the Phantom and saving the Vorcha's life.
So. Awesome. Also completely stupid and reckless because chances were more likely that I was just gonna trade him being sync-killed for me being sync-killed (especially since I was off-host and therefore lag), but I definitely felt like one mad mutha after that.