milman, you are lucky that you have inquired with this forum. scylla and others have given you the right advice, and it will be up to you whether you still consider your PR important or not, or whether you choose to do the right thing to keep your PR.
As scylla mentioned, while the lawyer probably had your best interest at heart, he was wrong in saying that you must have 731 days by the end of the validity of your PR card. You must have 731 days by the end of your fifth year anniversary of becoming a PR, which, in this case, the period that goes from May 2 2010 to May 1 2015.
In your case, if you come back on May 25 2014, then even if you do not leave Canada for even a single day, you still won't have more than 731 days at the completion of your fifth year (by May 1 2015).
So by May 1 2015, you will have stayed from
02 May 2010 to 27 March 2011 (which is 329 days)
27 May 2014 to May 1 2015 (which 339 days)
In total, it would only be 668 days. That in itself would already constitute a breach of the residency obligation, since a PR needs to be able to have at least 731 days in their first five years. By not complying, you risk of getting reported at entry.
http://laws-lois.justice.gc.ca/eng/acts/I-2.5/page-13.html#h-18
Now, let's assume you get in just fine without getting reported, and let's say you wait until June 30 2015. Because the considered residency window is ROLLING, then at the date of examination, which is June 30 2015, only days that you spent from July 1 2010 to June 30 2015 will be counted. So let's redo the calculation here:
July 1 2010 to 27 March 2011 (269 days)
27 May 2014 to June 30 2015 (399 days)
You would, in total, have 668 days within the considered residency window, and when you do submit your application on June 30, your application will be rejected, and they may even start the process to revoke your PR status.
Days outside of the considered five year window will start moving out of the considered residency window, and you won't be able to gain any extra days until you start replacing your absence in those five years. So if you come back on May 27 2014 (and enter unreported), the earliest that you can apply for PR card renewal would be 28 May 2016, by which you will have 731 days.
Nobody here said anything about the two years having to be consecutive. You just need to have at least two years in your first five years (since the day you landed). You won't have two years in your first five years (May 2 2010 to May 1 2015, NOT June 30 2015) if you come back in May 2014.
You need to come back by March 26 2014 AT THE LATEST to have any chance at all to still satisfy the residency requirements (this, already assuming you won't leave at all until May 1 2015). Delaying your return trip by 2 months would delay your eligibility for renewal by over a year, so keep this in mind.