The challenge is that EBS is attempting to gauge future results by past performance, which obviously doesn't include you moving from 8 hours per week to 60 hours per week on this project. It wasn't really designed with this use case in mind.
The best you can probably do is to look at the Burn Down chart and figure the impact of this event on the 95% probability line. When you look at the chart, you'll see how many hours are left to obtain the 95% probability of releasing on time; you also know how many hours you will have added to that by a certain date (the end of your "vacation").
We'd be very interested to hear how this works for you and where your final release date ends up. The most important part of Evidence-Based Scheduling is the "Scheduling;" that is, knowing how to apply your time/people resources to accomplish a goal (meet a release date). If this works or fails, it will speak to the accuracy of the Burn-Down chart and its usefulness.