I tried that this weekend and I could run past (or jump over) many of the mobs. While the amount of ammo spent on this one run was less than normal, so were the returns, but my "usual" 10-15 PED loss was still there. So whether I spend 16 PED in ammo or 30, it is likely I will still see my 10-15 ped loss. The markup on anything I get is nothing to speak of. I have done about 6 KEy1 instances and not a golden gear in the lot. They are fun, but I am not seeing the returns I would need to keep the "fun" going. I will run a few more...enough to finish my level 2 missions, but I will just stick with mining for better returns unless I find a way to make the Key instances more profitable. 60% to 70% returns are not sustainable...
I have run 37 Key 1's in the last 4 days and have found that it can be done killing as few as 72 mobs total, though I've only done that once, while the rest were 73-75 mobs killed. For the sake of comparison, my average cost (including key) was 34.42ped, while average loot was 30.00ped, for a tt return of 87.2%*. During that time, I've looted 24 gears and 348.92ped of Arkoins total, which works out to an average per key run of 9.43ped Arkoin and 0.65ped Gears. Though I suspect I've looted a higher than average number of gears, the rest of the numbers are fairly normal, I think. I ran three Key 1's killing all mobs a few weeks ago and my average cost was 43.60ped, while my average loot was 36.78ped. Based on other's comments and my results in other keys, though, I believe returns when killing all mobs will settle out around 75% and returns when skipping as many mobs as possible will settle around 85%. *I used Sollomate Opalo, Cryo III (L) and CalyTrek Spirit MKII (L) + Beast, no armor and a Regen Chip V (L) for heals (though I healed very little)
My experience is similar to this. I haven't totalled up my returns for the last 15 key 1's that I have run, but I can already see that the average return % is much higher than when I full clear. P.S. Sell me your gears please