Even understanding player abilities and different class abilities there are still fishy things that go on;
Case and point, 2nd to last doors in VS blow, I get sentinel sprint plus use my sage force speed. I don't get slowed up or touched on my way to defend the next section prior to the last doors. When I reach the far terminal for the force field, I see an operative 75% done planting a bomb on the door. Luckily I throw a FIB and stop him, but I still see no possible way he could have outrun me and capped the force-field terminal, dropped and be 75% done planting a bomb before I arrive at the final terminal location. I could live with him starting to cap the final terminal for the force field when I arrive, but not having already capped, dropped and almost planted on the next door.
That is just you being a noob.
Since he is the attacker, as soon as the previous doors dropped, he was killed. Since the doors are now down, he spawns AHEAD OF YOU in the final room, jumped down, and started planting. Some players even seek death as soon as they see their team has planted a bomb, and then just hold off on pressing the "Release" button until the door drops for a free teleport ahead of you.
Oops, I just gave away my secret strategy.