About my Zero offset synthetic VSP data, I thought something but I am not sure about the effect of this issue. If I get rid of the first three traces from the data before picking arrivals (deleting or killing), and continuing next process steps, that give rise to any effect for results? If not so, How should I write for getting rid of these three traces?

I added my screenshot (plus signs denotes picking) 

Thank you 

Best

Erdi