As it is practiced at a typical National event, it's more like 7~9 min....

It goes something like this:
Call the fencers.
"Undetermined amount of time" goes by, and it becomes clear to the referee that one of the fencers is missing. Pulls out the Yellow Card and begins to scan the immediate area for any sign of the fencer showing up (i.e. someone running toward this part of the venue in a mighty hurry).... and at the same time, look for any sign of spectators/fencers who might have a clue about the missing fencer's whereabouts (i.e. he went to the bathroom, sir!)....
Mark the offense on the slip and either walk over to the Bout Committee or send someone over, also taking an "undetermined amount of time" in the process.... Oftentimes, the messenger or the referee needs to wait a bit in front of the Bout Committee while a huge army of fencers with slips that need to be handed in, and or he/she can get the attention of whoever is in charge of the microphone at the moment.
2nd call is made over the P.A. system..... (at this point, the Red Card is effectively issued, and the referee notes it on the slip)
Referee walks back to the strip (or starts the clock on strip if a messenger was sent instead).......
Timer hits 0:00, Black Card comes out.....
Penalty is noted, the slip is signed, and off goes the "victor" to hand in the slip.
This whole process, on the average seems to take good 7~9 min in reality as the referees in general are very generous about giving fencers a reasonable time to report to the strip. Many referees are also well beyond their competition years, and tend to move at a leisurely pace.
This is just as well, considering in a typical US National event venue, there's a good share of inadequate PA system at times, limited seeding/pool posting spots, and plenty of confused fencers/parents.
But essentially, when it comes down to it, there are three penalties with two 1-min intervals in between. However, before the penalty process is initiated with the first Yellow Card, it does take some time to establish that the fencer is, in fact, missing. If there is any interpretation, that's where it is.
Once the process starts, there is no interpretation. Just a very generous referee with slow penmanship, and slow motion. Oh, and a stop watch that defies physics.
