With a casing on the porch, bullet under the house, and others in the living room, it doesn't seem that they took any time to torture him with a knife.
BJM did think he looked beaten but that would be with fists not a knife. She didn't say he was cut up or anything like that.
Shooting him and beating him was enough to try to get him to give out a combination if that is what they wanted.
But then
@Johnny B Bad did say that there was no reason to put the knife in cement if it wasn't used to cut someone.
I just can't see the reason for the Wagners to shoot 33 times, counting bullet under house, and maybe beat Chris, but then on top of that start cutting someone.
It isn't fitting the Wagner's MO for that night.
Hummm....