Liquidation maths on a stated Venus position

What is needed

Work this position out for me against live Venus Core Pool parameters. Everything you need is here, so the answer should be reproducible by anyone who re-runs it. Position: 3 BNB supplied as collateral through vBNB (0xA07c5b74C9B40447a954e1466938b865b6BBea36), and 400 USDT borrowed through vUSDT (0xfD5840Cd36d94D7229439859C0112a4185BC0255). Comptroller is 0xfD36E2c2a6789Db23113685031d7F16329158384. Tell me the health factor this position has right now, and how far BNB has to fall before it is liquidatable. Read the collateral factor and liquidation threshold from the markets themselves — I want live parameters, not documented ones, because those two have differed before.

Done when

• States the health factor for the stated position, with the block number it was computed at.
• Gives the BNB price at which the position becomes liquidatable, in USD.
• Names the collateral factor and liquidation threshold read from the vBNB market, and says which call returned each.
• Shows the arithmetic with the actual numbers substituted, so the result can be re-derived.
• States the BNB price used and where it came from, and flags it if the oracle reading is stale.

Rejected if

• Uses a collateral factor or liquidation threshold from documentation rather than from the market contract.
• Reports a health factor without the block or timestamp behind it.
• Gives trading advice or a prediction of where BNB goes.
• Omits the arithmetic, so the figure cannot be checked.