There seems to be a problem with how TextMate deals with processes run from a document. If you want your TextMate to become irresponsive, just do the following
1. Open a new document 2. Type "yes" 3. Press ^R 4. Voilá!
Of course what you do is to run into an endless loop here. But the problem is that the whole application becomes irresponsive. It really should not be as prone to errors in external programs, since this creates the risk of data losses.