The answer to both is it depends. There are so many variables and sometimes it's just pure luck, both good and bad. In an actual active shooter, and I mean officers literally moving to gunfire, the chances of the bad guy getting ventilated are high. Death is also pretty much guaranteed, but sometimes the bad guy lives. The chances of additional innocent victims shedding blood is also high, depending on their proximity to the threat and the threat's intentions. With the piece of shit in Texas, the chances of additional innocent victims is incredibly high, but it should've been incumbent on those officers to make entry the second one or two got on scene and limit any "extra" casualties. We used to train that the second 4 officers arrived at the scene, the 4 of you form a squad and make every. Now we're training to have just one maybe two make entry just because time is clearly off the essence.
The other thing is it's probably going to be the regular patrol officers making entry and not waiting on tactical teams to arrive. By the time the callout starts, you're looking at 30 minutes, minimum, before everyone is mustered and rolling to the scene. As we saw in Texas, 30 minutes is a lifetime.