When e-mail isn't fast enough and you really need to see a business contact in person, it is a very good idea to make an appointment.
Before you do something you'll regret, pick up the phone. Phone calls can connect the way they always have, just as we hope that, ideally, e-mails do....and will.
If you need information, keep trying to take the courteous route. If you don't, you may fall prey to one of the greatest temptations that happens when we are driven by personal ambitions to obtain answers we need to what we consider very pressing questions.
(Unfortunately, the questions that most often feel urgent to us may not seem as urgent to others. Additionally, it has been my experience that people who frequently have urgent questions are really urgently just seeking some kind of reassurance that he or she is liked. Truly.) This unfortunate need for attention and how it is expressed becomes especially awkward when you decide to follow your colleague into the bathroom and ask your pressing question while he/she is otherwise engaged. Even when you loiter politely by the towel rack or hot air dryer that stance is not a wise choice or allows for sufficient space to help someone to feel at ease who is shocked and aware that you are waiting, waiting, stalking, stalking. (That mumbling you hear from the other side of the stall door is that person calling home or the security patrol, and they are calling about you. Yes, you.)
Second to this choice in bad judgment of following someone into the restroom is what you consider the more polite choice of waiting outside the restroom to waylay the person on his/her way some place else, like a scheduled appointment for which he/she is focusing his/her thoughts in order to be ready for the meeting.
Now, it's true the person you have stalked to the restroom might greet you cordially upon exiting, but he/she most likely will have grown cold inside after realizing you have been waiting there, and smile only with the coldest of intentions right after he/she has decided that the flight/fight response triggered by the adrenaline rush of being startled and stalked by you has abated, along with her/his powers of concentration about the forthcoming meeting.
To avoid receiving a cold and deadly smile from someone who now sees you not as a person with a problem but who is one, remember that Queen Elizabeth was once accosted inside her toilette and she had the interloper's head chopped off.
One can't resort to such extremes in the workplace when one is stalked by people who frequently have emergencies that others have to handle for them or urgently need reassurances that he/she is liked. One can only say, no, to whatever favor you might urgently have wanted to ask and later post on one's blog: If something bad ever happens to me, go ask this stalker where he/she was when it happened.
The next time you have pressing issues at work, remember to respect the laws of courtesy and you will have a much stronger chance of receiving a favorable response to whatever urgent issue has driven you to become, instead of a co-worker, temporarily, a stalker.