I won't get into how you should have pitched it into a starter, and how you should be making a starter for any liquid yeast in a beer over 1.030.
But as to the "exploding" tube issue, it happens to all of us at least once. That's because the yeasties have been farting co2 while they hung out in the tube.
A couple of tips for handling that.
1) No matter what size the mouth of the vessel is that you use to make a starter use a larger funnel (like the ones you can get from your lhbs) sanitize it and holding the stopper end pointing downward "inside" the funnel, open slowly, that way as it gushes it mostly sprays into the funnel.
2) Have starsan or whatever no rinse sanitizer in a spray bottle, and spray the tube as well as your hands thoroughly with sanitizer, that way if it gushes onto your hands and falls you've been sanitized.
3) Open slowly....twist it only slowly enough to crack the "ratchet" ring on the tube, then stop a second to let some of the co2 woosh out, then open the tube.