I don’t understand that , but as I’m not a physicist, I’d guess that gravity exerts equal pressure all over the globe, so when you got to the middle, gravity would be neutralised and you’d stop in the middle.
Wherever you went in , it wouldn’t make any difference, you’d be falling down and slowing down ‘till you reached the centre then gravity from both ends would be equal and you’d stay in the centre.
It’s very simple really; where ever you stand on a globe, you look down to the ground and up to the sky.
Cheers.