So exactly the same as a mankad then?
I think there's an argument the ball is dead here, but that would be very generous to the batsman.
20.1 Ball is dead
20.1.1 The ball becomes dead when
20.1.1.1 it is finally settled in the hands of the wicket-keeper or of the bowler.
20.1.1.2 a boundary is scored. See Law 19.7 (Runs scored from boundaries).
20.1.1.3 a batsman is dismissed. The ball will be deemed to be dead from the instant of the incident causing the dismissal.
20.1.1.4 whether played or not it becomes trapped between the bat and person of a batsman or between items of his/her clothing or equipment.
20.1.1.5 whether played or not it lodges in the clothing or equipment of a batsman or the clothing of an fielder.
20.1.2 The ball shall be considered to be dead when it is clear to the bowler’s end umpire that the fielding side and both batsmen at the wicket have ceased to regard it as in play.
20.2 Ball finally settled
Whether the ball is finally settled or not is a matter for the umpire alone to decide.
The dead ball rule kind of contradicts itself in that the 1st bit says about just in the keepers gloves but afterwards it says about if the fielders and batsman regards it in play