In terms of tranquilizers, a lion can take 10+ min to become tranquilized, I assume a tiger would be similar. I’m not entirely sure, but I believe a large reptile would take a much longer time. As others have stated, the staff seemed to have at least attempted to separate the animals. Obviously, they couldn’t just go in there to separate them. A tranquilizer would probably take too long to measure the dosage and tranq the animals. I’m sure the staff took every precaution but unfortunately when working with wild animals there can be unpredictability. I can understand why you are furious about these deaths, but there’s no need to question the capability of the staff. Believe me, those keepers are as devastated as you are. But anyways, Welcome to Zoochat!
Wild animals, even the ones that are born and raised in captivity, are not 100% predictable. Even the best zoo (or sanctuary) in the world is going to have accidents, things going wrong. Hell, tigers fight and kill each other in the wild all the time, why would that be 100% preventable in captivity? If zookeepers were so incompetent, deaths like these would be waaaaaay more common.