I'm not sure I buy the idea

I'm not sure I buy the idea that a man with a knife in his chest can engage in several physical encounters and live...
I do buy the idea that a man can have a knife in his chest and live...
but being thrown around... and all that movement... I don't think its a good thing.
perhaps somebody can explain the feasibility of it all.

other than that... I liked the movie.

of course in the beginning... I thought the home owner would have been armed while answering the door of unexpected company.
kinda out there in the middle of no where... it seems a little too naive to be unarmed in that situation.