The entire key to this current process is to be able to pump mud into the well faster than it can be carried out by the fluids flowing out of the well. If they can’t do that they are wasting their time but I believe they CAN do this.
The well is flowing at something like 3 barrels per minute. if you can pump in 4 barrels per minute you will eventually kill the well assuming that the well is structurally intact downhole and doesn’t allow the mud being pumped in to flow out into the formation.
I think once the mud is flowing downhill they could begin lowering the pumping pressure then send down cement kind of like achieving balance against the formation pressure? just my 2cents.
It certainly looked like more than 3 barrels a minute in the video