 <p>Your question is not answerable. It depends entirely on whether the lock is contended or not.</p> <p>Let me put it this way: you're asking "does it take a long time to enter the bathroom?" <em>without telling us how many people are already in line to use it</em>. If there is never anyone in line, not long at all. If there are usually twenty people waiting to get in, perhaps very long indeed.</p>