Basically.
1. Convince someone you're giving them your bank because you're quitting.
2. Bring Rune Med+alch runes and your 100M+
3. Show them the 100M+
4. Quickly drop it and alch the Rune Med for 10k
(this works because 10k+ looks the same on the ground
5. Victim goes to grab coins in his bank
6. Barrage+DDS
7. Profit