Dont listen to johnny when he tells you to bail after the floor caves in instead look for that blue neon cross, theres a hole to the left you can crouch through. Moving back up through the building gets pretty intense with arasaka soldiers everywhere but keep pushing until you see the rescue objective pop up. Once you find takemura, help him fight through the rest and get him out safely. Pretty interesting actually, a lot of people miss this completely since the game doesnt make it obvious, but saving him changes things up especially if youre thinking about working with hanako later. Keeping him alive opens up some different story bits that you might want to see, and its worth the extra fight if youre curious about all the possible endings.