If you have passed the event horizon of a black hole then what speed would be necessary to escape?

I am aware that passing the event horizon would result in you being crushed but for the sake of argument lets say you had a shield of sorts. I am also aware that the time dilation because of increased gravity would cause problems to say the least but lets say that doesn't matter either. Finally how much faster than the speed of light would one be needing to traveling to escape the black hole at the centre of our galaxy, since i asume the size would matter ( not sure that anyone knows the size) but my main focus is on how to work this out. Thankyou