The Steps for Bringing Out Suspense (In a Scene)

The last page discussed an internal conflict over what she would do. This is an external problem she does not control.
Clearly stating the conflict. While there could be three possibilities, or infinite, typically there are just two. That's all the reader needs, and any more just makes it harder for you to explain and for the reader to process.
Alex sheds his guard like a loose blanket and starts hurdling chairs. Another guard -- unexplainably -- shouts at him to stop and then points his gun at Alex. I kick his gun to the side, but then it fires, hitting a tourist huddling against the wall in the leg. I start running towards Alex...
This is just events happening. Yes, it does serve to prolong, but in a minor way -- there is no focus on outcome as for the normal prolonging.
...and see him getting to the bomb with the red number on 5. He looks at it, biting his cheek. He doesn't know what to do. Five seconds until it explodes.

4. He's staring at it, studying it, meaningless wires, while I still run towards him. He can't decide on the play.

This is good prolonging. There are good reasons why fictional bombs are not equipped with a a simple off switch and have a visual timer. I have also starting tipping the odds: "meangingless wires".
3. When I'm in heaven, I will remember him like that -- running like a panther, then looking like a 12th grader when he didn't know what to do. 2. I get to Alex. We just look at the bomb. And . . . I'm spending the last two seconds of my life with Alex.
Prolonging, obviously. And tipping the odds as she assumes the bomb will go off. Note how I try to make this interesting -- there is more than just a countdown. The ending is interesting:
1. He reaches in and pulls out a bunch of random wires.


We both look at the zero. Nothing is happening. We're still alive! I'm still here! The bomb didn't go off!


He's in shock. He mumbles, "Something. I had to do something, Jade."

This was a "cheap" way out of the conflict. He didn't know what to do, he rips random wires, he gets lucky. But "I had to do something" functions as the path out, and was even meant as a moral.

The paragraph beginning "We both look at..." has no punch. Simply removing it works well (though there were slightly better options). I was thinking in terms of problem/resolution, so I was focusing on resolution and ignoring the little voice telling me that paragraph was too weak.

0. I stare at the zero, uncomprehending . . . finally realizing the bomb is not going off.

We're alive.

I pound on Alex's chest. "YOU HAD NO IDEA WHAT YOU WERE DOING."

By the way, him being in shock instantly transions into the problem of post-traumatic shock.

More Examples? Nah.

I would love to present more examples, but you have read enough. Creating suspense is one of the basic skills of a good writer -- analyze what other writers do.