I should add some details, because FIGunner has some good points and I didn't mention what else I have.
In my bino harness (I have the large Alaska Guide Creations), I include some minimal stuff to spend a (miserable) night.
As FIGunner said, when you find elk, you GO AT THEM!!! this might eventually result in a full-speed send off a glassing knob trying to cut distance.
Water tablets
Snickers
Protein bar
Havalon knife
Wind checker
Space blanket
Lighter
in theory, since I haven't had to do this yet, if I find elk that require such an aggressive assault, I could drop my pack, attach my InReach to my harness with the caribeaner, attach a Nalgene to my harness, sling my rifle and go like he!!
Whether successful or not, with just my bino harness I'd have what I need to spend a very long and uncomfortable night away from any semblance of camp. my rifle has a stock pack with 10 extra rounds in it, havalon has 10 blades in the case, I'd have enough food to get some calories back in me for a very minimal dinner and breakfast for the initial pack back to camp in the morning. Quarter the animal, remove back straps, tenderloin, neck and trim meat, Start a fire, huddle under space blanket, find a seep to get water, hydrate like crazy…. Spend the night thinking about how cool of a story you will have to relive for the rest of your life.
Of course, the better option is to keep your pack with you. The reality is that my camo pack has gotten itself lost a couple times in the heat of the moment (for example; if maybe I had a running shooting match with an animal that wasn't hit well on the first shot - which fortunately hasn't happened yet)
The Alaska Guide Creations X50 Classic MAX Bino Harness is built to accommodate full-size, 50mm binoculars. Protect your binoculars with this bino harness!
www.blackovis.com