Are the events in this manga panel happening simultaneously? I know manga is usually read right to left, top to bottom, but this panel confuses me a bit.



The guy on the right looks all annoyed and "!" first, and then we have the blonde sliding in like 'are you guys on a date too?', but chronologically isn't this a contradiction? Shouldn't we have seen the main character ask his question first and then spiky guy's reaction? 

Or is this panel showing things simultaneously?

If someone could show me in what direction/chronology I'm supposed to read/understand this, it'd really help.
This would be a personal answer based on my own experiences: in cases like these I interpret the height of the speech bubble as order. The left bubble is higher up than the right one, so that happens first. There's nothing stopping the right one to be placed higher up, as it wouldn't hide any important details or anything in the art. Therefore I would read the bubbles in this panel left to right. 

The following image is from http://shadow.randomfandom.com/gh/styles.htm and shows reading order. Look at number 4 and 5, that's how I interpret the two speech bubbles in your example.