I would not feel defenseless if all I had was my Beretta CX4 carbine...... with 20rds of 9mm at my disposal.

Rather have it than a pistol gripped shotgun......... never timed it but believe I could get off 4-6 aimed 9mm rounds in the time it would take "me" to get off 2 buckshot loads................with a pump gun.

As set up it's; IIRC , about 3-4 inches shorter than an AR with the stock fully closed...... the magazine (if you use a 18 round) is fully in the pistol grip and the white light is easy to operate. capable of rapid fire "fist" size groups at 50 yds...... 10yd half that.

Cover a choke point like the top of the stairs........... and call 911