Plot hole: There's no way that Eddie and Nana left the flooded theater without getting a single drop of water on them. The water flooded up to the ceiling and there's no other way to exit besides the front doors, and Moon's secret exit, which also floods. They do not leave through either way.
Deliberate mistake: The morning after the flyers are spread, Buster is sleeping in a drawer. When his alarm clock goes off, he hits his head at the top of the drawer, but later on, he can be seen standing up in it, easily visible when he is putting his coat on. The drawer obviously became wider for him to stand up in it.
Continuity mistake: When the gang arrived for their first day of closed rehearsals the clock on the front of the theater says about 8:30, but just a few minutes later when Buster goes to get the power back on the clock now says about 11:50.
Other mistake: When Buster Moon is calling out the solo acts for final selection he calls Daniel's name with no megaphone and Daniel can hear his name fine. Then when Buster is making the selecting the solo finalists, Daniel cannot hear him, requiring Buster to use a megaphone to talk to him.
Plot hole: After Moon gives his first pep talk about working harder than ever to the contestants, Eddie asks loudly "What about the hundred grand?!" in earshot of most of the contestants. The contestants (especially Johnny or Pete) would have heard that question and started asking their own. (00:24:50)
Other mistake: Considering how famous Nana Noodleman is it's odd that everyone is surprised that she's still alive.
Other mistake: When Mike finishes his song and the audience begins applauding him, you can see the microphone cord dangling from somewhere above the sets, despite it previously having its stand on the stage. This is obvious when he's swinging from it. What is it hanging from, thin air? There was nothing he could attach it to while swinging; the cord should've snapped rather than holding.
Factual error: The police are circling the theatre to find out where Johnny's escaped father is. During this, you can see that Mike is getting pulled upwards towards the copters like a piece of metal getting attracted to a magnet. Helicopters create downdrafts - Mike should've been blown away from the stage rather than being pulled up.
Answer: I think he escaped from the bear with his girlfriend, sped off very fast and the bears fell off the car.
You haven't read the question. Before it cuts to Meena's performance, the lead bear popped up from behind the car and presumably kidnapped them.