Also, force is not a factor on kicks going into R's EZ since these kicks are always a touchback regardless of who supplied the force. So had this play been a kicking play with R catching the ball at the three and his momentum taking him into the EZ, it would be the same result (a safety) as it couldn't have been a kick that put the ball into the EZ or it would be a touchback. So for the play to remain live a new force has to have put the ball into the EZ which is R catching at the 3 and carrying it into the EZ. As Calhoun explained no more momentum exception when the ball leaves the EZ. I only bring this up to try and help understand that the force was not the pass in the OP was not the pass but B's carry, so its not the force that is getting "disqualified", it is the momentum exception, the force is the reason it is a safety as B put the ball into the EZ.
Also interesting is if B had intercepted in the EZ instead of the 3, then it would be better for A to decline the hold as if the penalty would be accepted the basic spot would be the 20 and the penalty would be enforced all but one from the 14 to the 7. Declining the penalty would give B the ball at the 4. See 10-4-6.