Is this a plot hole? (spoiler)
At 1:13:01 in my version of DVD, Simon has collected three watches which show 6:04:57. But after he gets stabbed in the eye by Kate(at 1:22:36), Simon says he waited for a long time for payback, and from his appearance it is obvious that at least some days have passed.
Now the real problem is that it is HIS watch that read 6:05:46 when Kate realized she was to jump out. Has exactly one or two days plus 49 seconds have passed in Simon's reference of time?
In an extra clip ("alternate ending") the boss says Kate spent 6 minutes and 59 seconds in the cube. Then whose frame of reference has Jerry's watch been in? If not only many alternate realities but many timelines are crossing over in this hyperspace, can a watch indicate an absolute time?
Maybe then, this cube has not started at 6:00:00. Then what is the point about all the setting -- "6:59 elapsed" and calculations of the dead scientist?