Nifty- Always in long, but unclear- stay out

1) I don't like to trade against big empty space (moves are never smooth and sometimes reverse abruptly
2) In situations like this, a systems trader does well than a discretionary trader.

questions
1) Why not look to buy a pullback?
Most likely best choice of strategy, but to me, it still looks like a trapping move

2) Why not sell
No sign of weakness as yet so no shorts