Short answer: yes!
There are a number of related questions on the use of dialogue tags and pauses in passages of speech you can look through for more information, such as How do we handle pauses in a dialogue.
The problem that jumps out to me is that dialogue tags and actions take time to read and therefore serve as the pauses between spoken lines. If there's too much action, it causes a delay in the conversational rhythm.
All of dialogue has a rhythm, and people reading the dialogue will infer the rhythm from what is on the page. If this were music, the pauses would be demarcated by rests between notes, and they indicate a certain length. In language, the word choice and phrasing have their own rhythm. Longer syllables are slower; short indicative or imperative sentences without filler can be snappier, and they all take some amount of time. Think about the characters' speech as the music notes, and the pauses as the rests, and make the dialogue tags or descriptive actions between lines of dialogue take the same time to read as you want the pause to last. (Full disclosure, I wrote this paragraph in response to the question linked above.)
What to do with your passage? Cut down and space out the action. For example:
"Was that your dream job?," Sam asked, "Being a cop?" He opened the passenger door for Robert to jump in.
"Yes," Robert sighed, "I wanted to be a cop." He made himself comfortable and buckled up.
"Huh.*" Sam shut the door, rounded the hood of the car, opened his own door, and seated
himself, all the while looking bemused.
As he buckled his seatbelt he turned to Robert and said, "It's kind of
ironic, really,* because you look like a thug. You dress like one at
least."
Robert didn't know how to respond to that, but Sam had already
dismissed the topic and begun whistling as he started the engine.
As you can see, I kept most of the dialogue and most of the action. I just redistributed it and made a few adjustments to them to a) keep that rhythm flowing and b) round out the scene.
The small details I completely dropped, such as closing and locking the driver's door, were sacrificed on the altar of pacing. The reader probably won't miss it because we see him buckling up and starting the engine. Why? The door would have been shut out of habit sometime between sitting down and starting the engine, no problem. Locking the door is such an insignificant plot detail that to include it would probably call undue attention to it-- people may assume it is an instance of Checkhov's gun and expect it to become relevant when they get carjacked at the next stoplight.
*This was a bigger change, but here's why I did it: It would take time for "Sam" to make it to the other side of the car, so this response doesn't flow naturally-- the surprise of "Oh, really?" should be blunted by the physical limitations. The other reason I changed the longer line, unrelated to the rhythm, was because he asked the question about Robert wanting to be a cop, which implies he was considering the possibility already-- therefore it doesn't feel right to have his reaction be so demonstrably taken aback. The other way to fix this would be to change the very first line into a sarcastic joke implying that Sam knows (surely but inaccurately) that Robert would never have considered a career as a cop.
Now the pacing is better, but I think the actual mechanics of getting into the car are still tedious. If they're not important to the plot or the characters, try to replace them with something that is, or drop them altogether. Sam walking around the car takes up the time he needs to ponder, but you could just as easily fill it with Robert's observation of the bobble-headed Ganesha figurine that Sam has attached to the dashboard.
