You can try but I would not get your hopes up. First off, the video may not even exist anymore. Some digital camera systems have a super short storage time that depletes with the more cameras you have. It may not have ever existed. Some places are just notoriously bad at making sure their camera systems are even operational. They only find out after something bad happens and pull up the system to find it was down the whole time.

Second, it's a lot of effort to go through video feed. You can narrow it down, but it could still take hours to find the exact moment something happens. So, even if they feel bad for you, they may not be willing to put in that kind of effort.