Should the Vault Dweller delay the attack, in order to speak to Zimmerman again you must directly select the dialog option, Razor replies that this may not be a good idea.
After choosing the above dialog option, entering Adytum, and returning, Razor will have disappeared. None of the other Blades react to this, and it is impossible to launch the Blades' attack on the Regulators. After eliminating them single-handedly, however, Razor reappears in the Blades' hideout, implying that she fled the area to escape Regulator reprisal.
If you say to Razor to talk to Jon and entering the area back where the Blades are, she becomes dead (her "legs" can be seen). If you attempt to loot her (even if there is nothing on her) and going back to the area, only bloodstain appears.