Death Machine

The film starts out with a scene at a demolished roadside diner, with everything inside slaughtered by a malfunctioned secret project by the codename Hardman, invented and manufactured by Chaank, a megacorporation producing various military hardware. Public outcry ensues, and Cale is introduced as the company's investigating Chief Executive. Ridley, head of the board of directors, tries to cover things up, but she gets the wind of all the illegal activity going on in the company. Cale demands immediate and full public disclosure, along with Dante, who works on numerous projects, including the Hardman, being fired. This doesn't seem to get much of a reaction from anyone besides Dante himself who takes an eerie interest in Cale, confronting her on a few occasions with knowledge about her finances, past life, and ID information.Meanwhile Cale wants to know what project Dante is currently working on in vault 10 (apparently mechanical shops in the building are designated as vaults), as he never submits reports and is being less than cooperative. Ridley, scared, refuses to help, telling her outright that her recently deceased predecessor who took interest in Dante's work ethics soon met with a grisly death right in the corporate headquarters, most likely by the very project Dante is working on. During the conversation she steals his access card in order to investigate on her own.At the same time a trio of stoner pacifist eco-warriors are planning an infiltration of the company's headquarters in order to destroy its digitally stored assets and put Chaank out of business.Somehow, Dante finds out that Cale has the card now, and confronts Ridley on the issue, soon after killing him by what the viewer can assume is his invention. Carpenter calls up Cale the same night after finding Ridley's mutilated body by means of implanted life-sign transmitter that everyone in the corporation has. She arrives, and finds out that whatever it was that killed him came out of the infamous vault 10, and taking matters in her own hands, terminates Dante's employment and seals the vault. Dante is about to shoot her when the trio of eco-warriors show up and take them hostage. They need to gain access to the secure areas of the building in order to destroy the company's digitally stored bonds, but Cale refuses to cooperate. Raimi, apparent leader of the gang, goes to an alternate plan to cut through the doors and the bulkhead leading to the containment. Dante, sensing his chance, "helps" them by suggesting to cut through one of the vaults surrounding the containment instead, leading them to what is revealed to be vault 10.Once the vault is open, he jumps in, activates his invention (he calls it the Warbeast, or Frontline Morale Destroyer as that seems to be its official designation and purpose), which promptly kills off one of the teammates, Weyland. Raimi flees for his life, meeting up with Yutani and subdued Cale and Carpenter, when Dante broadcasts his demands on the monitor, demanding his employment reinstated, and Cale "interfacing with him on a regular basis". Raimi and Yutani terminate the operation and attempt to get out of the building, with Carpenter and Cale tagging along.

Question: Who kills Ridley?
Answer: Dante