If I try to remember his previous fights, I don't think he has ever planned anything, just reacted when things started to happen, and, fortunately for him, at that point he has had pretty quick wits. Who knows why he never plans anything beforehand, even in extremely simple situations like this when he already realised he must do something.

His power is strange, thinking about it based on this episode and the loli teacher's explanation. ESP is altering reality, so what exactly is Touma doing? Removing ESP alterations? What does that exactly mean? It means Touma has the exact same power as any esper or magician he meets, only he can't control it and it always just reverses what was done - unless that would be inconvenient for the script writer in which case his power does nothing. It's kind of boring, really. I hope they will spend time to probe it sufficiently.