This is not quite that but it will help you understand:
You put 17 btc to buy btc contracts at btc price 6000$. Bitmex took your btc as deposit and put its $ to buy you btc contract (you own them 17*6000=100k but they dont have to worry because they have your 17 btc worth 100k and your contracts worth 100k). Now, when price is at 3000$ you still own then 100k $ (because they spend that much for your contracts) but your deposit is worth 17*3000$ =50k now (and your contracts another 50k) - together worth 100k - last time to close for bitmex to cover your depth. Thats why there is liq price. This is example of buying 17 btc in contrancs for 17 btc. You bought 18. Thats why adding 1 btc as deposit wont delete liq price.
Othervise its impossible to buy btc for btc.
Where do you see that i have 100k dollars worth of contract? I Understand average price entry is $6019.38 but i am wondering how you got to 100k number?