The ACU Control Center/Escape Pod is a detachable part of the ACU made available though a researchable upgrade for the ACU. It is available to all factions and is functionally identical but asthetically unique for all 3 factions, being based on the command center "head" of the Armored Command Unit.
When the ACU gets into a difficult situation and faces destruction, it is possible to detach the top portion of the ACU from the rest of the unit and escape. The body of the ACU is destroyed without any explosion, collapsing on the ground and leaving a reclaimable wreck behind. The "death nuke" now only occurs if the Control Centre is destroyed. (Unless of course the Core Dump ability has been researched)
The Escape Pod is unarmed, can fly faster than gunships but is slower than fighters, bombers & fighter/bombers. Its only function is to rebuild the body of the ACU at the cost of 1500 Mass, 7500 Energy and 3 minutes of your time. After completion of the body somewhere on the ground, the head immediately reattaches. The Escape Pod is classified as an air unit, so anti-air units will attack it. It is also worth noting that since the pod is at gunship-level, it can be fired on by regular and experimental gunships too. Therefore, attempting to escape in the Control Center is only effective when fleeing from Eagle Eyes or ground based units with limited anti-air capabilities.
If they have not researched core dump, sometimes a Commander will use their ACU/Control Center as a last ditch attempt to harm their enemy by just dropping a little nuclear gift on their doorstep. However, in a 1v1 Assassination match this is obviously completely useless as it will cost a commander the match. In a Supremacy or team match though, players may occasionally have the opprtunity to make a useful kamikaze attack but it rarely alters the tide of battle.