Mj and flange fittings to hook up a fireman and tee off before for my conn.

[solventweld36]

This guy working for us hooked up a 18" coupling mj to mj but didn't realize the pipe would go through with no stopper so he made the connection like a normal mj ro cast and only put the 4" pipe a couple inches in the coupling. Will this blow out or what? All the info I can get is appreciated