Regarding safety door

Which safety door are you talking about, because your own door is safer and when it is locked from inside or outside, you are secured.

The builder is right in informing that you cannot encroach common area for any reason.

If your tower is completed, then you gather members of the tower and form an association if the builder is not cooperating.

The builder has no rights to stop you from forming an association, but you may have to get it registered once formed so that the builder cannot interfere in it.

Then the builder will handover the building to the association along with the related apurtenances. 

If your door is locked outside and inside then what is the problem?  How can you encroach on another area?   Your apartment owners can meet and form a flat owner's welfare society and get it registered till the building society is formed.

How an additional door, whatever name is called, enhance safety? Any how, you cannot occupy the common area.