The VCA in my modular has a manual level control that actually goes "below" zero.
For cases like this, I would tune down the manual level until the drone cuts out.
Maybe yours does as well? (My VCA is a custom design - I'm not sure what your Eurorack VCA's capabilities are.)
If not, maybe you can mix a negative voltage into your VCA's CV port, and tweak it until it just cuts off the drone.