Why is the runway blocked?
Can you confirm what scanario 3 means?
Are these sim exercises that you have had? Or real encounters?
I wouldn't get too caught up in thinking about them as non standard situations. Simply break them down into go-arounds
On the 737, the 2 engine go-around function requires
1. a decision to go-around.
2. Use of toga. 1 press = a more gentle climb, 2nd press gives you the full performance, which you probably won't need in most cases.
3. A call- 'Go around-flap15'
When you hit toga, the go around sequence has begun, and because you are single channel, you won't have the autopilot. Fly the LNAV go around procedure.
Get the positive rate- gear up.
Flaps will be bugged, and retracted as you pass the bug (speed tape)
(If you are already at flap15, make sure the other bloke/person doesn't give you something less useful)
Make sure that you always, ALWAYS, set the go around altitude as soon as you capture the glideslope.
I'm not entirely sure what your scanario 3 means. A little more information would be useful. Do you mean that the aircraft is suddenly turning with the ILS captured?