Agreed, but you are already relying on things outside the PSK (the stainless steel water bottle in your pack, remember?). I suggest adding the AMK bivy bag or equivalent to your pack as well.

But for all I know that pack may already have a tent inside - in which case the bivy bag is just dead weight. But for day hikes a lightweight bivy bag is a great asset.

Myself, I carry a bivy bag three times the weight of the AMK. Probably three times the packing volume as well. But my bivy bag doubles as comfort item on lots and lots of lunch breaks through the years - it splits open and can be used as a lean too or wind breaker for a whole group. A true multi purpose item, but with a weight penalty for its more robust quality: Strong fabric, good zippers and solid grommets for tying. For emergency only use I'd stick with the AMK bivy bag or the slightly bigger, but somewhat insulated "blizzard survival bag" (google and you'll find it).