We don't even have to talk about high and low, just lower. Not every scene has the same level of tension, conflict, stakes, whatever. Some are lower. Ckatt is asking about those.
I try to approach such a scene in terms of what a character wants. To continue with the example provided, the detective wants some answers--maybe to some specific questions, maybe just poking around trying to sniff out a break. In any case, it's a scene in between scenes, moving the story along, surely necessary but not high stakes.
OK, so, don't give him what he wants. The person being questioned refuses to answer. Or lies and the detective knows it. Even if the lead gained from the scene turns out to be a dead end, it's not won without a bit of conflict. With that established, there's room for layers. Maybe the detective employed more force than necessary, threatened needlessly, or lied himself. Maybe he made a promise he's going to have to keep later but doesn't want to. Entanglements.
Anyway, the key is to have some small thing that's wanted by a character and they don't get it. Or get it delayed, or only in part. Anything except getting exactly what they wanted.
There are other angles to take. For example, the detective might get a surprise--a bit of kindness, or courage, or even a physical surprise. Lucky break. Enough to keep going to the scene where there's real payoff. Since we're on the subject of detectives, Raymond Chandler does this well.