If considering the crunch of our spacetime and masses (like a huge black hole), as the event horizon becomes the 'out there' with no more out there beyond the event horizon of the final 'hole', there is no place for this energy to sweat to ... this beast has yet to be mathematically defined so it is not possible to yet calculate what will happen when the universe crunches (if the universe does). As Physicist cited, the spacetime bubble appears to be speeding up in its expansion, so the likelihood of gravity from existing masses stopping then reversing the expansion appears to also be out.
The eventual cold final destiny appears to be in the future at about 10 to the 120th power years away. For science to change this perspective, some other means to transfer the energy radiating from black holes (or perhaps some other energy radiating by some means other than x-rays and into a quantum well outside our spacetime) will have to be theorized so that even if the crunch runs, it can culminate in some where/when.
With the initiating event of the 'big bang' space, time, and energy were involved in the expansion. The inflationary phase would have stretched the spacetime bubble much faster than light speed, but at some where/when the inflation would slow and the colled spacetime bubble would allow condensation of intitial masses (those sub-atomic building thingies that form sub-atomic particles of protons and electrons and neutrons). Much later the cooling would allow for first atoms to form and gravity would begin to act in the spacetime bubble.
There is no 'center' to the spacetime bubble, per se, but if we run the expansion backwards, there does appear to be a mathematical where/when which was the initial bang event. The term bubble is somewhat misleading because the universe of spacetime isn't really 'spherical', per se, even though running the expansion backwards evidences a common where/when for the start. When science refers to the 'shape' of the universe, it is in reference to the mathematical curvature or non-curvature rather than a volumetric shape since this curvature is to be thought of as having an element of dimension time integrated into the curvature.