Absolutely normal to peak at the Start of an encounter. Having your trinkets procced, the prepot rolling and all the big cooldowns at Hand like a murder of crows and Stampede. I peak at 400k+ and fall back to 250k er something (depending on fight)
Also try to get as much agi as you can as survival. You are sagnificantly over the hitcap. Try to change some agi/hit gems to pure agi if the socket bonus isn't hat good. (Cant check them because fuck smartphones^^)