a) You can still be constantly stunned... interrupting you.
b) You can be knocked down, interrupting you AND removing you from cover.
c) You can be pulled out of cover, interrupting you again.
d) you can be pushed out of cover, interrupting you yet again.
For being a stationary target... cover is rather ****. People can do everything to you they can do to a normal person, but you're not moving, so they can LOS you.