I don't know how SLS's escape tower works and I expect your right with respect to it. However that's not true of all escape towers. The escape tower used fo

I don't know how SLS's escape tower works and I expect your right with respect to it. However that's not true of all escape towers. The escape tower used for the Mercury-Redstone missions at least was meant to only work when the rocket below it was no longer accelerating. This became a factor during the (unmanned) Mercury-Restone 1 incident, where the launch tower flew off when the rocket was still on the launchpad, leaving the capsule behind on the rocket because the capsule was only designed to detach when the rocket was in freefall (it wasn't in freefall, because it was still on the launchpad.)