Of course any involvement of Paul Rudd was going to be an up, because, well, it's Paul Rudd, but the trailer's stinger works well on a few levels.
Firstly, after a whole lot of intensity and emotion, it provides a nice bit of comic relief, with Rudd's Scott Lang on top form. However, even though Lang being there at all is a surprise after the end of Ant-Man and the Wasp, it simply opens up more questions than it does give anything away.
How did he escape the Quantum Realm? How will he go about taking the others back into it? It's going to be hugely important to the movie, and it sets that up nicely while being genuinely funny too.
NCTJ-qualified journalist. Most definitely not a racing driver. Drink too much tea; eat too much peanut butter; watch too much TV. Sadly only the latter paying off so far.
A mix of wise-old man in a young man's body with a child-like wonder about him and a great otherworldly sensibility.