" On a liquid fueled booster, you can rapidly reduce thrust but that's harder to do with a solid."

Well - the sort of situation where one might use a launch escape system is the sort of situation where you dont have much say in what the booster itself is doing. It's either going off course, has given up, or is heading toward some sort of catastrophic failure. To say that you can throttle a liquid booster before using an escape mechanism is to assume you will always have control of the vehicle when needing the escape mechanism.

In any case - all you need is to get the capsule 'out the way', and that involves a fairly large ammount of thrust (but remember, it's only lifting the CM which is compartively small ) to lift it away from the stack, and a tiny nudge to get it on a different trajectory, so the booster or what remains of it sails on by.

Analogy - you're stood on train tracks and a train is heading towards you. Dont start running down the track away from it - just take two steps to the left :)

http://www.answers.com/topic/apollo-spacecraft

The Apollo CM was about 5.8T, and the escape mechanism was 689kn - potential for 12G of acceleration there - and it only needs a brief second of that to get well out of the way of even a 4 or 5 G accelerating booster. One presumes the two figures of CM mass and escape tower thrust would scale together to the new CM for the new vehicle design.

Doug