Carry on regardless?

Soo... Your sewing away and your machine starts to make an odd noise and feel a little weird when sewing do you...

A. Carry on regardless and hope that "All is well"
or
B. Immediately stop sewing and check it out. Re-thread the machine and grab a piece of scrap fabric to test it out

If your answer is B well done, your a better person than I think most of us are! :)
If your answer is A then your probably going to end up with something like this

Eeek what a mess, Its a good job that it is on the inside and the top stitching looks fine otherwise I would be screaming right now.

What are you making do I hear you say, well I'm attempting the Sew Weekly Pillowcase challenge, ok I know its late but I had a bit a of faff trying to find some funky pillow cases.  I admitted defeat with this when I found these

EXTRA LARGE!!! Win! So I decided to attempt a shirt out of them (they are humongous!) and I'm a little concerned about how easily they came apart.  I mean I pulled at a thread and it just unraveled on me... Worrying!