Edit 2 (a day later): AP did their own video analysis and came to slightly different conclusions: https://lemmy.world/post/7113210
Tl;dw: Decent video evidence shows that the rocket the IDF claims hit the hospital was in fact intercepted and destroyed by the iron dome missle defense system. Thus it's unlikely the hospital was hit by an errant missle fired by Hamas or other Palestinian groups.
Edit 1: If there was another missile, wouldn't it be seen in the video like the other missiles?