I'm not sure you would ever see a runner round up
When it comes to time, 3:43 generally means anything sub-3:44, and 3:43:59 means anything 3:43:59.99999999 or under. At least that is how I view it. So you're just fine. Anyways, they won't kick anyone out for something like that. Technically, at least in previous years, they would accept you even if you had run 3:45:59 (i.e. they allowed 59 seconds over qual time).