Lifters have an electric solenoid attched to them
Said solenoid opens a bleed valve in the lifter. Thus basically collapsing it. Which allows the outer shell to still movebut internally it no longer pushes the the pushrod up to open valves.
Each lifter drops one at a time over a few milliseconds. So you never feel it.

One thing to keep in mind for maint on an mds equipped car. Proper oil changes and viscosity are paramount.