Weird update time

I tried to find what in my application that takes so much CPU usage and why I get so long waiting times so I started to log some stuff in my application. When I logged every part in my application I ran into this:

var updateTime = process.hrtime();

Nightclubs.update({_id: nightclubId}, {$push: { guests: {
  value: value,
  currentGuestAmount: currentGuestAmount+value,
  date: thisEntryDate.toDate(),
  gender: gender,
  age: age,
  guard: guardId
}}})

var updateDiff = process.hrtime(updateTime);

Later in the method I log this time like this:

console.log('update benchmark took %d nanoseconds', updateTime[0] * 1e9 + updateTime[1]);

Which result in this:

update benchmark took 1084353904561267 nanoseconds

Yep… That is 1.8 WEEKS… This is really weird since the method in total takes 916589992 nanoseconds, or 0.91 seconds (which still is a bit too long)

Does any one have any clue about this?

PS, A bit of details on what data I insert:

guests: { type: Array, defaultValue: [] },
'guests.$': { type: Object },
'guests.$.value': { type: Number },
'guests.$.currentGuestAmount': { type: Number },
'guests.$.date': { type: Date },
'guests.$.age': { type: Number },
'guests.$.gender': { type: String },
'guests.$.guard': { type: String },