The problem with this poser is it assumes a universal concept of space and of time. There IS NO SUCH 'at that moment' that has uniform applicability to remote locations, and neither is space 3-dimensional like a two-by-four. Whenever you use the phrases 'at that moment' and 'at that place' you cannot equate them meaningfully to anything but the speaker's frame. This post is actually a plug for http://www.ezrelativity.tk -- a non-commercial site. I recommend its visitation!