ACE Elevators had a staff of more than 20 ppl working in the towers of the WTC - They all made it out alive.
If indeed the elevators had the high explosive/superthermite charges attacking the core, they could have been brought in all at once and kept on the maintenance floors.
see http://www.911blogger.com/node/12743#comment-170341

How about WeAreChange web interviewing the surviving ex elevators staff of WTC on any unsual events before the 11th of September 2001. Questions like unsual maintenance work on the elevators weeks before 911. Or any sign of radio transmission devices being put in. ( it is much easier to have radio controlled explosives than cable laid explosives which would be too visible and time taking to install.)
Their replies will be interesting to analyse by world wide experts.

Yours John