The fire truck was flipped and moved to the side of the runway, this was not 24mph. 24mph is the final groundspeed recorded after the aircraft skidded off of the runway.
Per the ADSBx track the plane was at 101kts (115 mph / 185kph) just before crossing taxiway D, which would be where it hit the firetruck. It still had enough energy afterwards to reach taxiway E, 600ft away.
The results seem on the high end but they check out at first glance.
A plane is basically a flimsy tube. A firetruck is a solid brick comparatively. The plane out weighs the fire truck by a lot and out speeds it by a lot. So yeah, destroying the whole front of the plane to punt the truck it sounds about right for a 25 on 5 or 35 on 10/15 type rear ending to me. Flipping doesn't really sound that unreasonable considering that the plane made contact with the top of the truck (just by virtue of comparative height) and contact may not have been straight on. Even if it left the pavement on it's wheels airport firefighters aren't exactly who I'd bet on (they're middle of the pack) to keep the truck on it's wheels if they got surprise kicked off the road especially if there's an embankment involved.
Okay that makes far more sense the article didn’t really make that clear to me.