Slash resistant clothing

Unlikely. The shirt looks like it's made to take the pressure of the knife over a large area but if the pressure is put into a small area it would still go through. It might weaker it a bit though.

A slash IS a lot of pressure on a small area. That's kinda how you cut things. And with a box knife specifically, you have to initiate the cut with the point. If the point's not breaking through now, it's unlikely it will break through in a real stab.

When you hold a knife for a slash it takes the entire pressure of the blade ~evenly on an area but with a stab the tip hits first. Think the difference between a belly flop and a swan dive.

Not with a box knife.

Box knives are still angled =P

They have a flat blade. You can't slash with a flat blade unless you begin with either a hack or a stab. A box blade is too small to hack, so you must initiate with a stab.

Imagine dropping a pairing knife on your forearm, blade side horizontal, from about 6 inches. Probably be fine. Do it point side down and you'll need a bandaid.

Not with this fabric.

And your analogy is completely irrelevant to our argument.