In the slo-mo, looks like an M67, but submerged in a dug-out maybe 2 or more metres deep (the angle is steep on a dug-out), it looks mostly real to me. Thats a lot of water weight wise to push up and out. Plus the soft mud too, would absorb much of the shock.
So, no doubt at the end of the day its untrained plugs in the hands of stolen ordnance. Like one would rip his teeth out pulling the pin the John Wayne method. Must have been altered a bit before hand.
Its all fun til someone looses an eye..... then its a sport 8)
Wes