You still hold the keys and can withdraw at any time. That's the point if non-custodial DeFi.
If you withdraw more than your interest and in some other crypto than your collateral then your loan now has leverage. During that particular withdraw transaction you will have signed some logic which can automatically liquidate your lent crypto if the amount you withdrew (minus interest) becomes worth less than your collateral.
Until that pre-signed liquidation transaction executes you are fully in control of the balance and keys.
