Not exactly a nitpick but when Mac and Dave are having the conversation while digging the hole, Dave tells Mac what he's been through as a POW and that he was digging his own grave once which resulted in his humiliation instead of his death.
In the conversation Dave says: 'I know what that sounds like.'
Mac replies with: 'Just the truth.'
After that phrase Dave's watch bleeps. It's just a single bleep as when you would start pushing the buttons on your watch.
Listen carefully though. A quick single bleep. Could've been 8, 9, 10 a.m.
Besides you could clearly see their watches while digging and Dave was wearing a digital watch.