I would think facilitating payment would only leave you liable for the amount given to you to transfer, not the amount of your assets that total the amount of debt between the parties you are facilitating for.
If Alice owes Bob $500, and I've agreed to take Alice's $5 bill to Bob, and I accidentally give Bob my own $500 bill, Bob doesn't get to keep it. The liability I took on in that transaction is for the amount of money I accepted from Alice for the purpose of delivering to Bob, not Alice's total debt.
If Alice owes Bob $500, and I've agreed to take Alice's $5 bill to Bob, and I accidentally give Bob my own $500 bill, Bob doesn't get to keep it. The liability I took on in that transaction is for the amount of money I accepted from Alice for the purpose of delivering to Bob, not Alice's total debt.