If it was team sabotage:
1. At the time this happened, the map did not show any explosives from my team. The video is set in slow motion so others could analyze the video in more detail.
2. He was also out of the line of fire with his Desert Eagle 44 to shoot the explosives if planted by my team on the ground floor.
If it was his own explosive or his team's explosive:
1. It must be a M2-SLAM, C4 or M15-AT-Mine because he was playing an engineering class but he can not detonate it with his Desert eagle 44 on Conquest Large map normal mode settings.
2. Shooting explosives on the ground floor from above with a pistol is out of his line of fire.
3. The explosive from his team is not shown on the map, but this is moot because it wouldn't be shown on the map if it wasn't spotted by me or my team unless it's a DS-3 Decoy.
4. If the explosive was thrown by his team on the first floor to ground floor, it is also out of his line of fire, as in point 2 above.
Perhaps he can prove all the above is wrong by providing a gameplay video replicating how he did it with the Desert Eagle 44 to make multiple kills twice, as in the video above.